India is the seventh largest country of the world in area and the second most populous country. It lies wholly in the Northern and Eastern hemispheres. The mainland of India extends between latitudes 8°4' N and 37°6' N and longitudes 68°7' E and 97°25' E. The Tropic of Cancer (23°30' N) passes through the middle of the country and divides it into almost two equal parts.

The Tropic of Cancer passes through eight Indian states — Gujarat, Rajasthan, Madhya Pradesh, Chhattisgarh, Jharkhand, West Bengal, Tripura and Mizoram. The north-south extent of India is about 3,214 km, and the east-west extent is about 2,933 km. The total area of India is about 3.28 million square km, which is roughly 2.4 per cent of the world's total land area.

The southernmost point of the mainland is Kanyakumari (Cape Comorin), but the southernmost point of India as a whole is Indira Point in the Nicobar Islands of the Andaman and Nicobar group. The northernmost point is near the Siachen region of Kashmir. The standard meridian of India is 82°30' E, which passes through Mirzapur in Uttar Pradesh. Indian Standard Time (IST) is five and a half hours ahead of Greenwich Mean Time (GMT+5:30).

India has a land frontier of about 15,200 km and a coastline of about 7,516 km including the islands; the mainland coastline alone is about 6,100 km. India shares its land borders with seven countries — Pakistan and Afghanistan in the north-west (India claims the whole of the old princely state of Kashmir including the region bordering Afghanistan), China, Nepal and Bhutan in the north, and Myanmar and Bangladesh in the east. Sri Lanka is separated from India by the Palk Strait and the Gulf of Mannar. The Maldives lies to the south of the Lakshadweep islands, and Indonesia is our maritime neighbour across the sea. Politically, India has 28 states and 8 Union Territories. The states which touch international borders are 17 in number, and the state of Sikkim was the last state to be merged (1975) as an Indian state.

Key points to remember:

• India is the 7th largest country by area and 2nd by population.
• India lies between 8°4' N and 37°6' N latitudes and 68°7' E and 97°25' E longitudes.
• The Tropic of Cancer passes through eight states of India.
• The standard meridian 82°30' E passes through Mirzapur; IST is GMT+5:30.
• Kanyakumari is the southernmost point of the mainland; Indira Point is the southernmost point of India.
• India's coastline is about 7,516 km including islands.
• India has seven land neighbours — Pakistan, China, Nepal, Bhutan, Myanmar, Bangladesh and Afghanistan.
• The Palk Strait separates India from Sri Lanka.

The Indian subcontinent has a very ancient and varied geological structure. It can be divided into three broad geological regions: (1) the Peninsular block — the oldest part of India, made of very ancient rocks (Archean gneisses, Dharwar schists etc.). Geologically it is a part of the ancient Gondwana land and is a stable block of hard rocks; (2) the Himalayas and the Indo-Gangetic plains — these were formed when the Tethys geosyncline (an ancient sea between the Gondwana land and the Angara land) was squeezed and folded, and the northern drift of the Indian plate pushed against the Asian plate. This is why the Himalayas are young, folded and still rising mountains; (3) the coastal plains and islands — formed later by the deposition of rivers and the sea.

On the basis of relief, India is divided into six major physiographic divisions: (1) The Himalayan mountains, (2) The Northern (Indo-Gangetic) plains, (3) The Peninsular plateau, (4) The Indian desert, (5) The Coastal plains, and (6) The Islands.

1. The Himalayas: young fold mountains running in an arc from the Indus in the west to the Brahmaputra in the east, about 2,400 km long and 240–320 km wide. They are divided into three parallel ranges from north to south — the Greater Himalaya (Himadri) with the highest peaks, the Lesser Himalaya or Himachal, and the Shiwalik (outermost foothills).

2. The Northern plains: formed by the alluvium brought by the Indus, Ganga and Brahmaputra rivers, stretching from Punjab to Assam, about 2,400 km long and 240–320 km broad. These are among the most fertile and densely populated plains of the world.

3. The Peninsular plateau: the oldest and most stable landmass, lying south of the northern plains, with the Aravali hills in the north-west, the Vindhya and Satpura ranges in the middle, the Malwa plateau, the Chotanagpur plateau and the Deccan plateau further south, flanked by the Western Ghats and Eastern Ghats.

4. The Indian desert: the Thar desert in western Rajasthan, with the Aravalli range on its east.

5. The Coastal plains: the narrow strips along the Arabian Sea (western coastal plain with Konkan, Kannad and Malabar coast) and along the Bay of Bengal (eastern coastal plain with Coromandel and Northern Circars coasts).

6. The Islands: the Andaman and Nicobar group in the Bay of Bengal and the Lakshadweep group in the Arabian Sea.

Key points to remember:

• Geologically India has three broad regions: Peninsular block, Himalayas with Indo-Gangetic plains, and coastal plains with islands.
• The Himalayas are young fold mountains formed by the folding of the Tethys geosyncline.
• The Peninsular plateau is the oldest and most stable part of India, a part of Gondwana land.
• India has six major physiographic divisions.
• The Himalaya has three parallel ranges — Himadri, Himachal and Shiwalik.
• The Northern plains are formed of alluvium brought by the Indus, Ganga and Brahmaputra.
• The Thar desert lies in western Rajasthan.
• The Lakshadweep islands lie in the Arabian Sea and the Andaman-Nicobar islands in the Bay of Bengal.

The Himalayas are the highest and one of the youngest mountain systems of the world. They run in an arc of about 2,400 km from the Indus gorge in the west to the Brahmaputra gorge in the east, and are 240–320 km wide. The Himalayas are divided into three parallel ranges from south to north:

1. The Shiwaliks (Outer Himalaya): the southernmost foothills, made of unconsolidated sediments brought by rivers. They are low (900–1,200 m) and broken by many gaps. The Jammu hills, the Punjab hills and the outermost hills of Nepal belong here.

2. The Lesser Himalaya or Himachal: a middle range (average height 3,700–4,500 m), which includes the famous hill stations of Kashmir valley, Kullu, Shimla, Mussoorie, Nainital and Darjeeling. Important ranges of this zone are the Pir Panjal, the Dhaola Dhar and the Mahabharat range.

3. The Greater Himalaya or Himadri: the highest and northernmost range, with an average height of about 6,000 m. It contains the highest peaks of the world — Mount Everest (8,848 m, in Nepal), K2 or Godwin Austen (8,611 m, in the Karakoram), Kangchenjunga (8,586 m, the highest peak of India, on the Sikkim-Nepal border), Nanga Parbat (8,126 m) and Nanda Devi (7,817 m). The glaciers of the Himalaya feed the great rivers; the largest glacier outside the polar region is the Siachen glacier (about 76 km) in the Karakoram, and the Gangotri glacier is the source of the Ganga.

Trans-Himalayan ranges lying north of the Himadri are the Karakoram (with the highest peak K2), the Ladakh and the Zaskar ranges, and the Tibetan plateau. The famous passes of the Himalaya include the Zoji La, the Shipki La and the Nathu La (through which India trades with China), the Bomdi La, the Jelep La, the Rohtang Pass (connecting Manali and Lahaul-Spiti), the Banihal Pass and the Burzil Pass. In the eastern Himalaya the mountains run almost north-south and are called the Purvanchal; they include the Patkai, Naga, Manipur and Mizo (Lushai) hills.

The Himalaya is divided from west to east into the Punjab Himalaya (between the Indus and the Sutlej), the Kumaon Himalaya (between the Sutlej and the Kali), the Nepal Himalaya (between the Kali and the Tista) and the Assam Himalaya (between the Tista and the Brahmaputra). The highest peak of the Assam Himalaya is Namcha Barwa. The Himalayas act as a climatic barrier, protect India from the cold winds of Central Asia, and intercept the monsoon clouds, giving rainfall to north India. For Assam and the north-east, the Patkai and eastern ranges matter most; the Brahmaputra flows through a gap in the Himalaya.

Key points to remember:

• The Himalaya is divided into Shiwalik, Himachal (Lesser) and Himadri (Greater) ranges from south to north.
• Mount Everest (8,848 m) is the highest peak in the world.
• K2 (8,611 m) is in the Karakoram; Kangchenjunga (8,586 m) is the highest peak of India.
• Nanga Parbat and Nanda Devi are other high peaks of the Indian Himalaya.
• The Siachen glacier is the largest glacier outside the polar region.
• Zoji La, Nathu La, Shipki La, Rohtang and Banihal are important Himalayan passes.
• The eastern Himalaya is called the Purvanchal; it includes Patkai, Naga, Manipur and Mizo hills.
• The Assam Himalaya lies between the Tista and the Brahmaputra; its highest peak is Namcha Barwa.

The Northern Plains, also called the Indo-Gangetic Plains, form one of the largest and most fertile alluvial plains of the world. They were formed by the deposition of alluvium brought down by the Indus, the Ganga and the Brahmaputra and their tributaries. The plains stretch from Punjab in the west to Assam in the east, about 2,400 km long and 240–320 km wide, and cover the states of Punjab, Haryana, Delhi, Uttar Pradesh, Bihar, Jharkhand (partly), West Bengal and the Brahmaputra valley of Assam. These plains are the most densely populated region of India and are the heart of Indian agriculture — they are therefore called the 'granary of India'.

The northern plains are divided into four belts from north to south:

1. The Bhabar: a narrow belt of coarse pebbles and stones lying along the foothills of the Shiwaliks, where the rivers disappear underground.

2. The Terai: a marshy, damp and thickly forested belt south of the Bhabar, where the rivers reappear on the surface. The Terai is famous for its fertile soil and, in recent times, for sugarcane, rice and tea cultivation and for wildlife sanctuaries.

3. The Bhangar: the older alluvium of the plains, which forms high terraces above the flood level. It contains calcareous concretions called 'kankar'. The soil of the Bhangar is less fertile.

4. The Khadar: the newer alluvium, deposited by the rivers every year in the flood plains. The Khadar soil is very fertile.

The plains are divided into three great river basins or sections: the Punjab (Indus) plains in the west (formed by the Indus and its tributaries — the Jhelum, Chenab, Ravi, Beas and Sutlej; the Punjab plains of India are drained by the Ravi, Beas and Sutlej), the Ganga plains in the middle (stretching over Haryana, Delhi, UP, Bihar and West Bengal; the Ganga is joined by the Yamuna at Allahabad/Prayagraj, and the Ghaghra, Gandak and Kosi from the north), and the Brahmaputra plains in the east (the valley of Assam). The Kosi is called the 'sorrow of Bihar' because of its frequent floods, while the Damodar is called the 'sorrow of Bengal'. The northern plains also contain the world's most extensive stretch of fertile alluvial soil and support intensive agriculture.

Key points to remember:

• The Northern Plains are formed of alluvium brought by the Indus, Ganga and Brahmaputra.
• The plains are divided into Bhabar, Terai, Bhangar and Khadar belts.
• The Bhabar belt lies along the Shiwalik foothills; the Terai is marshy and forested.
• The Bhangar is older alluvium with kankar; the Khadar is new, fertile floodplain alluvium.
• The Ganga meets the Yamuna at Prayagraj (Allahabad).
• The Kosi is the 'sorrow of Bihar'; the Damodar is the 'sorrow of Bengal'.
• The Punjab plains are drained by the Ravi, Beas and Sutlej in India.
• The Brahmaputra valley of Assam is the eastern extension of these plains.

The Peninsular plateau is the oldest landmass of India, a part of the ancient Gondwana land made of hard crystalline rocks. It is roughly triangular in shape, broader in the north and tapering towards the south. It is bounded in the north by the Vindhya and Satpura ranges and in the north-west by the Aravali hills.

The plateau is divided into two main parts: (1) the Central Highlands — the Malwa plateau lying north of the Narmada, the Aravali range on its north-west, the Vindhya range and the Chotanagpur plateau in the east (with the highest peak of the plateau, Parasnath, 1,366 m); and (2) the Deccan plateau — a triangular plateau lying south of the Narmada, made of black basaltic lava (Deccan trap), bounded by the Satpura range in the north, the Western Ghats in the west and the Eastern Ghats in the east. The Deccan trap region is famous for its black (regur) cotton soil.

The Western Ghats (Sahyadri) run along the western coast from the Tapi river to Kanyakumari, about 1,600 km. They are continuous and higher (average 900–1,600 m). Their highest peak is Anamudi (2,695 m), which is also the highest peak of peninsular India, in the Anaimalai hills of Kerala. Other peaks are Dodabetta (2,637 m, the highest peak of the Nilgiri hills) and the Palghat, Bhorghat and Thalghat are important passes/gaps of the Western Ghats. The Western Ghats receive heavy rainfall from the Arabian Sea branch of the monsoon.

The Eastern Ghats run along the eastern coast and are lower (average about 600 m) and discontinuous, broken by the rivers Mahanadi, Godavari, Krishna and Kaveri. Their highest peak is Mahendragiri (1,501 m). The famous hill station of the south, Ooty (Udhagamandalam), lies in the Nilgiri hills, which is the meeting point of the Western and Eastern Ghats.

The Coastal Plains: (1) The western coastal plain is narrow (about 50 km). It has three sections — the Konkan coast (Mumbai to Goa), the Kannad or Karnataka coast and the Malabar coast (Kerala, which is the southern part). The western coast is generally rocky and has lagoons called backwaters in Kerala. (2) The eastern coastal plain is wider and flatter with large deltas. It has two sections — the Northern Circars (from Odisha to Andhra) and the Coromandel coast (from the Krishna delta to Kanyakumari). The eastern coast receives rainfall mainly in winter from the retreating monsoon and from cyclones; the famous deltas of the Mahanadi (Odisha), Godavari, Krishna (Andhra Pradesh) and Kaveri (Tamil Nadu) make the eastern plains very fertile. The Sundarbans delta (Ganga-Brahmaputra delta) is the largest delta in the world.

Key points to remember:

• The Peninsular plateau is the oldest landmass of India, part of Gondwana land.
• The plateau has the Central Highlands (Malwa, Aravali, Vindhya, Chotanagpur) and the Deccan plateau.
• Parasnath (1,366 m) is the highest peak of the Chotanagpur plateau.
• The Deccan trap gives the black cotton (regur) soil of the Deccan.
• Anamudi (2,695 m) is the highest peak of the Western Ghats and of peninsular India.
• Dodabetta is the highest peak of the Nilgiri hills; Ooty lies there.
• The eastern coastal plain has the Northern Circars and the Coromandel coast.
• The Ganga-Brahmaputra (Sundarbans) delta is the largest delta in the world.

The Indian desert, called the Thar desert or Marusthali, lies in the western part of Rajasthan and extends into Gujarat and Pakistan (the Cholistan desert of Pakistan is its continuation). It is a region of extreme heat in summer and cold in winter, receiving very little rainfall (less than 25 cm a year). The only river of the Thar is the Luni, which flows into the Rann of Kutch. In the north of the desert there are the salt lakes of Sambhar (the largest salt lake of India, in Rajasthan), Didwana, Pachpadra and Lunkaransar. The Aravalli range forms the eastern boundary of the desert; on the west the desert merges into the Rann of Kutch of Gujarat. The desert is crossed by the Indira Gandhi Canal (formerly Rajasthan canal), taken from the Sutlej (through the Harike barrage), which has turned some dry areas into fertile fields. Sand dunes and shifting sands are the main features; the region is sparsely populated and supports pastoral life and crops like bajra and pulses where irrigation reaches.

The Islands: India has two main groups of islands. (1) The Andaman and Nicobar islands in the Bay of Bengal: these are a group of about 572 islands and islets, of which about 38 are permanently inhabited. They are the peaks of an underwater mountain range that connects the Arakan Yoma of Myanmar with Sumatra of Indonesia. The Andaman islands are separated from the Nicobar islands by the Ten Degree Channel. Barren Island in the Andamans has the only active volcano of India, and the Narcondam island has a dormant volcano. Port Blair is the capital of the Union Territory. The islands receive heavy rainfall and are covered with dense tropical evergreen forests; the famous tribes of the Andamans are the Great Andamanese, Onge, Jarawa and Sentinelese. India's southernmost point, Indira Point, is in the Great Nicobar island.

(2) The Lakshadweep islands in the Arabian Sea: a group of 36 islands (of which 10 are inhabited) lying about 200–400 km off the Kerala coast. These are coral islands (atolls) formed by the accumulation of coral skeletons. The name Lakshadweep means 'one hundred thousand islands'. Minicoy (with the southernmost island of the group) is the largest island, and the group is separated from the Maldives by the Eight Degree Channel. The people are mostly Muslims; coconut cultivation, fishing and tourism are the main activities. The capital is Kavaratti.

Key points to remember:

• The Thar desert is in western Rajasthan; its only river is the Luni.
• The Sambhar lake is the largest salt lake of India.
• The Aravalli range forms the eastern boundary of the Thar desert.
• The Indira Gandhi Canal (from the Sutlej) irrigates part of the desert.
• The Andaman and Nicobar islands are in the Bay of Bengal; the Ten Degree Channel separates them.
• Barren Island has the only active volcano of India; Indira Point is in the Great Nicobar island.
• The Lakshadweep islands are coral atolls in the Arabian Sea; Kavaratti is the capital.
• Minicoy is the largest island of Lakshadweep; the Eight Degree Channel separates it from the Maldives.

The Himalayan rivers are perennial (they flow throughout the year) because they are fed both by rain and by melting snow and glaciers. Three great systems drain the Himalaya: the Indus, the Ganga and the Brahmaputra.

The Indus system: The Indus (Sanskrit name Sindhu) originates near the Mansarovar lake in Tibet, close to Mount Kailash. Its total length is about 2,900 km, of which only about 1,114 km lies in India; the rest flows through Pakistan into the Arabian Sea near Karachi. In India the Indus flows through Ladakh. Its main tributaries in India and Pakistan are:

• The Jhelum: rises from the Verinag spring in Kashmir; it flows through the Wular lake and is joined by the Kishenganga.
• The Chenab: formed by the union of the Chandra and the Bhaga near Keylong in Himachal Pradesh; it is the largest tributary of the Indus in terms of volume of water.
• The Ravi: rises near the Rohtang pass.
• The Beas: rises near the Rohtang pass and joins the Sutlej at Harike (Punjab).
• The Sutlej: the longest tributary of the Indus, which rises near the Rakas lake in Tibet and enters India through the Shipki La pass.

By the Indus Water Treaty of 1960 (brokered by the World Bank), the three eastern rivers — Sutlej, Beas and Ravi — were allotted to India, and the three western rivers — Indus, Jhelum and Chenab — to Pakistan. The Bhakra-Nangal dam on the Sutlej is one of the biggest multipurpose projects of India.

The Ganga system: The Ganga (length about 2,525 km, of which about 2,070 km in India) is the largest river basin of India, covering about 26 per cent of the country. It rises as the Bhagirathi from the Gangotri glacier at Gaumukh in Uttarakhand. The Alaknanda joins the Bhagirathi at Devprayag, and from there the combined river is called the Ganga. It emerges from the mountains at Haridwar and flows through the plains of Uttar Pradesh, Bihar and West Bengal. In Bangladesh it is called the Padma, where it is joined by the Jamuna (the Brahmaputra) and the Meghna and falls into the Bay of Bengal, forming the world's largest delta — the Sundarbans.

Main tributaries: The Yamuna (the largest tributary, rising from the Yamunotri glacier), which is joined by the Chambal, Betwa and Ken from the peninsular side before it meets the Ganga at Prayagraj (Allahabad); the Ghaghra, the Gandak and the Kosi (the 'sorrow of Bihar', which rises in Nepal); and the Son (from the south). The Hooghly, on which Kolkata stands, is a distributary of the Ganga (the Bhagirathi-Hooghly channel). The river is associated with the great cities of Haridwar, Varanasi, Prayagraj, Patna and Kolkata.

Key points to remember:

• Himalayan rivers are perennial — fed by rain, snow and glaciers.
• The Indus rises near Mansarovar in Tibet and is about 2,900 km long.
• The Sutlej is the longest tributary of the Indus; the Chenab has the largest volume of water.
• The Indus Water Treaty (1960) gave the eastern rivers (Sutlej, Beas, Ravi) to India.
• The Ganga rises as the Bhagirathi from the Gangotri glacier.
• The Alaknanda meets the Bhagirathi at Devprayag; from there the river is called the Ganga.
• The Yamuna is the largest tributary of the Ganga; they meet at Prayagraj.
• The Kosi is called the 'sorrow of Bihar'; the Hooghly is a distributary of the Ganga.

The Brahmaputra system: The Brahmaputra rises from the Chemayungdung glacier near the Mansarovar lake in Tibet, where it is called the Tsangpo. It flows eastwards along the northern side of the Himalaya, takes a sharp turn around the Namcha Barwa peak and enters India through Arunachal Pradesh, where it is called the Siang (Dihang). Near Sadiya in Assam it is joined by the Dibang and the Lohit, and from there it is called the Brahmaputra. In Bangladesh it is known as the Jamuna, where it joins the Padma (Ganga) and the Meghna and falls into the Bay of Bengal. Its total length is about 2,900 km, of which about 916 km lies in India. In Assam the river is wide, braided and constantly shifting, carrying a huge load of silt; the great river island of Majuli (world's largest river island) lies in it. The river is famous for the largest volume of water carried by any Indian river. Important tributaries of the Brahmaputra are the Subansiri (the largest tributary), the Manas, the Sankosh, the Dhansiri and the Tista. The Brahmaputra is also called the 'Red River' and, together with the Ganga, forms the world's largest delta. The Barak is the other great river of Assam — it rises in Manipur, flows through the Barak valley of Assam and enters Bangladesh, where it is called the Meghna.

The Peninsular rivers are non-perennial, flow through hard rock valleys and have broad, shallow valleys with little water in summer. Most of them flow eastwards into the Bay of Bengal, but two important rivers flow westwards into the Arabian Sea:

• The Narmada (about 1,312 km): rises at Amarkantak in Madhya Pradesh, flows through a rift valley between the Vindhya and Satpura ranges, forms the Dhuandhar falls near Jabalpur, and falls into the Gulf of Khambhat through an estuary. It is the longest west-flowing river of peninsular India.
• The Tapi (about 724 km): rises near Multai (Betul) in Madhya Pradesh, also flows in a rift valley, and falls into the Gulf of Khambhat. The Mahi and Sabarmati are other west-flowing rivers of Gujarat.

East-flowing rivers: the Mahanadi (rises in Chhattisgarh, crosses Odisha, the Hirakud dam is built on it), the Godavari (the longest peninsular river, about 1,465 km, called the Dakshin Ganga, rising at Trimbakeshwar near Nasik and falling into the Bay of Bengal near Rajahmundry), the Krishna (rising at Mahabaleshwar, about 1,400 km long, with the Tungabhadra and Bhima as tributaries and the Nagarjuna Sagar and Srisailam dams), and the Kaveri (rising at Talakaveri in the Brahmagiri hills of Karnataka, flowing through Karnataka and Tamil Nadu, with the famous Mettur dam, falling into the Bay of Bengal near Poompuhar). The Mahanadi is called the 'sorrow of Odisha'.

Lakes of India: Wular (largest freshwater lake of India, in Kashmir), Dal (Kashmir), Chilika (largest brackish water lagoon of India, in Odisha), Pulicat (second largest brackish lake, on the Andhra-Tamil Nadu border), Sambhar (largest salt lake of India, Rajasthan), Loktak (Manipur, famous for its floating phumdis and the Keibul Lamjao national park — the only floating national park of the world), Vembanad (largest lake of Kerala), Kolleru (Andhra Pradesh) and Pangong Tso (a brackish lake in Ladakh partly in Tibet). The largest artificial lake of India is the Govind Ballabh Pant Sagar (Rihand reservoir) in Uttar Pradesh.

Key points to remember:

• The Brahmaputra rises as the Tsangpo in Tibet and enters India as the Siang.
• Majuli, the world's largest river island, lies in the Brahmaputra.
• The Subansiri is the largest tributary of the Brahmaputra.
• The Barak rises in Manipur and becomes the Meghna in Bangladesh.
• The Narmada is the longest west-flowing peninsular river; it rises at Amarkantak.
• The Godavari is the longest peninsular river (the Dakshin Ganga).
• The Hirakud dam is on the Mahanadi; the Mettur dam is on the Kaveri.
• Wular is the largest freshwater lake and Sambhar the largest salt lake of India.

The climate of India is described as a tropical monsoon type, but because of its great size and varied relief it has many sub-types — from the frozen heights of the Himalaya to the hot Thar desert and the wet rainforests of the north-east. India has two main seasons of the year in popular understanding, but officially the year is divided into four main seasons.

The monsoon is the most important feature of the Indian climate. The word 'monsoon' comes from the Arabic word 'mausim', meaning season. The monsoon winds blow from the sea to the land in summer (the south-west monsoon, June to September, which brings most of India's rainfall), and from land to sea in winter (the north-east monsoon, which gives rain mainly to the Tamil Nadu coast). The monsoon reaches Kerala around 1 June (the 'burst of monsoon'), reaches Mumbai around 10 June, Delhi around 1 July and by mid-July it covers the whole country. The withdrawal begins from north-west India in early September.

The four seasons of India:

1. The cold weather season (winter), December to February: temperatures are low, especially in the north; the north-east trade winds blow; rainfall is negligible except in Tamil Nadu (from the retreating monsoon) and in the western Himalayas (westerly disturbances bring snow).

2. The hot weather season (summer), March to May: the sun's rays fall vertically; in north-west India hot dry winds called 'loo' blow; local thunderstorms like 'Kal Baisakhi' (Norwesters) occur in Bengal and Assam; mango showers occur in Kerala and Karnataka.

3. The advancing monsoon (rainy season), June to September: the south-west monsoon brings about 75 per cent of the annual rainfall; it is irregular and uncertain and breaks into 'breaks in the monsoon'.

4. The retreating monsoon, October to November: the monsoon withdraws; clear skies return; cyclonic depressions form in the Bay of Bengal and bring heavy rain to the Tamil Nadu (Coromandel) coast; October is called the 'season of retreating monsoon' and the state of Assam and the north-east receive good rain in this transition.

Special features and terms to remember: The monsoon is a 'connecting link' of the Indian economy because agriculture depends on it. 'Monsoon burst' is the sudden onset of the monsoon. Mawsynram (Meghalaya) is the wettest place on earth (about 1,187 cm average rainfall), Cherrapunji receives very high rainfall, and Jaisalmer (Rajasthan) is among the driest. The amount of rainfall decreases from east to west in the northern plains. India receives most rainfall from the Arabian Sea branch in the western coast and the Bay of Bengal branch in the north-east. The two branches of the monsoon meet in the Punjab-Haryana region. El Nino and La Nina affect the Indian monsoon — El Nino (warming of the Pacific) is generally associated with weak monsoon and drought in India.

Key points to remember:

• India has a tropical monsoon type of climate.
• The word monsoon comes from the Arabic word 'mausim'.
• The south-west monsoon gives India most of its rain (June to September).
• The monsoon first hits Kerala around 1 June.
• Winter (Dec–Feb), summer (Mar–May), advancing monsoon (Jun–Sep) and retreating monsoon (Oct–Nov) are the four seasons.
• Kal Baisakhi (Norwesters) and mango showers are summer phenomena.
• The retreating monsoon gives rain to the Tamil Nadu coast in winter.
• Mawsynram in Meghalaya is the wettest place on earth.

Soil is the uppermost layer of the earth's crust in which plants grow. The soils of India are classified into eight main types by the Indian Council of Agricultural Research (ICAR):

1. Alluvial soil: the most widespread soil of India, covering about 40–46 per cent of the total area, found in the northern plains and river deltas. It is formed by the deposition of river silt, is very fertile, and is divided into Khadar (new alluvium) and Bhangar (old alluvium). It is best for wheat, rice, sugarcane and pulses. The northern plains and the deltas are the 'granary of India'.

2. Black soil (Regur): also called black cotton soil, found mainly in the Deccan trap region of Maharashtra, Madhya Pradesh, Gujarat, Karnataka and Andhra Pradesh/Telangana. It is formed from lava rocks, is rich in iron, lime and potash but poor in nitrogen and humus. It is sticky when wet and develops deep cracks when dry, so it is called self-ploughing soil. It is best for cotton.

3. Red soil: found in Tamil Nadu, Karnataka, Andhra, Odisha, Jharkhand and Chhattisgarh. It is formed by the weathering of old crystalline rocks; red in colour due to iron oxide, poor in nitrogen, phosphates and humus. It is suitable for millets, pulses, groundnut and cotton.

4. Laterite soil: found in high rainfall areas of Kerala, Karnataka, Maharashtra, Odisha, West Bengal (and parts of Assam and the north-east). It is formed by intense leaching of the soil in heavy rain; rich in iron and aluminium oxides but poor in lime and humus. It is suitable for tea, coffee and cashew; when it dries it hardens like a brick and is used in building (the word laterite means brick).

5. Mountain/forest soil: found in the Himalayan region and hill areas, generally thin, acidic and rich in humus; suitable for tea, coffee, spices and temperate fruits.

6. Desert (arid) soil: found in the Thar desert of Rajasthan, sandy and saline, poor in humus and nitrogen, but becomes fertile with irrigation; the Indira Gandhi Canal has made parts of it cultivable.

7. Saline and alkaline soil: found in dry and poorly drained areas (parts of Gujarat, Rajasthan, UP, Punjab and Haryana), white in colour, rich in salts, and generally unfit for agriculture unless reclaimed.

8. Peaty and marshy soil: found in areas of heavy rain and high humidity where there is much vegetation (Kerala, coastal areas and parts of the north-east), rich in organic matter and humus but acidic; suitable for rice.

Soil erosion and conservation: the main agents of soil erosion are running water, wind, shifting (jhum) cultivation, over-grazing and deforestation. Methods of soil conservation are afforestation, contour ploughing, terrace farming, strip cropping, bunding and shelter belts. In Assam and the north-east, jhum cultivation causes serious soil erosion, so terrace farming and afforestation are encouraged there.

Key points to remember:

• Alluvial soil is the most widespread soil of India.
• Black (regur) soil is best for cotton and is found in the Deccan trap area.
• Red soil is red due to iron oxide and is poor in nitrogen.
• Laterite soil forms in high rainfall areas by leaching and is used to make bricks.
• Mountain soil is found in the Himalaya and is suitable for tea and fruits.
• Desert soil of Rajasthan becomes fertile with irrigation.
• The main causes of soil erosion are water, wind, jhum cultivation and over-grazing.
• Contour ploughing, terrace farming and afforestation check soil erosion.

Natural vegetation means the plant life that grows naturally without human help. India has a rich variety of natural vegetation because of its varied climate, relief and soil. The forests of India are broadly classified into five main types:

1. Tropical evergreen (rain) forests: found in areas of very high rainfall (over 200 cm) — the western slopes of the Western Ghats, the north-eastern states (including Assam) and the Andaman-Nicobar islands. The trees are tall, dense and do not shed their leaves at one time; they are called evergreen because the trees remain green throughout the year. Important trees are ebony, mahogany, rosewood, rubber and cinchona. These forests are rich in teak, bamboo and many medicinal plants; the Assam valley and its hills have some of the finest evergreen forests of the world.

2. Tropical deciduous (monsoon) forests: the most widespread forests of India, found where rainfall is 100–200 cm — most of the plains and plateaus. They are of two kinds — moist deciduous (with teak, sal, sandalwood) and dry deciduous (with tendu, palas, axlewood). The trees shed their leaves in the dry season. Teak and sal are the most valuable trees of these forests.

3. Thorn (desert) forests: found in areas of low rainfall (less than 50 cm) — Rajasthan, Gujarat and the dry parts of the Deccan. The trees are short, thorny with thick leaves; kikar, babool and khair are common. Cactus and other succulents grow here.

4. Montane forests: found in the mountain regions. In the Himalaya they change with height — tropical forests at the foothills, subtropical pine forests, temperate forests of oak and deodar in the middle, alpine grasslands and shrubs above, and bare snow at the top. In the south, the montane forests of the Nilgiri, Anamalai and Palani hills have sholas and grasslands.

5. Mangrove forests: found in the deltas and tidal areas of the coasts. The Sundarbans delta of West Bengal has the largest mangrove forest of the world, famous for the Royal Bengal tiger. Other areas are the deltas of the Mahanadi, Godavari, Krishna and Kaveri, and the coastal areas of Gujarat (Kutch). Mangroves act as a shield against cyclones and tidal waves.

Forest cover and protection: According to the India State of Forest Report, forest cover is about 21.7 per cent of the total geographical area. Among the states, Madhya Pradesh has the largest forest cover, followed by Arunachal Pradesh and Chhattisgarh. In percentage terms, the highest forest cover of the total area is in Mizoram, followed by Lakshadweep and the Andaman-Nicobar islands. The highest percentage of forest cover in relation to total area among the states is in Mizoram. Social forestry, agro-forestry and joint forest management are being promoted to increase the green cover. For Assam, the reserved forests, the Kaziranga grasslands and the Manas forests form a valuable part of the natural heritage.

Key points to remember:

• India has five main types of natural vegetation.
• Tropical evergreen forests grow where rainfall is over 200 cm.
• Tropical deciduous (monsoon) forests are the most widespread forests of India.
• Teak and sal are the most valuable trees of the deciduous forests.
• Thorn forests grow in low rainfall areas like Rajasthan.
• Montane forests change with height in the Himalaya.
• The Sundarbans is the largest mangrove forest of the world.
• Madhya Pradesh has the largest forest cover among Indian states; Mizoram has the highest percentage of forest cover.

Agriculture is the backbone of the Indian economy. About 54 per cent of the total land of India is cultivable, and about 60 per cent of the people depend on agriculture for their livelihood. India has two main cropping seasons: the Kharif season (sown with the onset of the monsoon, June–July, harvested in September–October) and the Rabi season (sown in winter, October–December, harvested in March–April). A third season is the Zaid season, in between, for short-duration crops like watermelon and cucumber.

Kharif crops: rice, maize, millets (jowar, bajra, ragi), cotton, jute, groundnut and sugarcane.

Rabi crops: wheat, barley, gram (chana), peas, mustard, rapeseed and oilseeds.

Major crops of India and their leading conditions/states:

• Rice: the staple food of India, requires high temperature and heavy rainfall or irrigation. It is grown mainly in West Bengal (the largest producer), Uttar Pradesh, Punjab, Tamil Nadu, Andhra Pradesh, Bihar, Odisha and Assam. West Bengal is the largest rice-producing state.
• Wheat: the second staple food, needs cool winters; the largest producer is Uttar Pradesh, followed by Punjab and Haryana (the Green Revolution states).
• Jowar: Maharashtra is the largest producer.
• Bajra: Rajasthan is the largest producer.
• Maize: Karnataka is the largest producer.
• Cotton: needs black regur soil and bright sunshine; Maharashtra is the largest producer (the largest producer of cotton in India), followed by Gujarat and Telangana.
• Jute: called the golden fibre; needs high temperature, heavy rain and alluvial soil; West Bengal is the largest producer; Assam also produces jute.
• Tea: needs warm, moist climate, hill slopes and well-drained soil; Assam is the largest producer of tea in India and the Brahmaputra valley is the largest tea-growing region of the world.
• Coffee: Karnataka is the largest producer, mainly in the Kodagu (Coorg), Chikmagalur and Hassan districts.
• Sugarcane: Uttar Pradesh is the largest producer, followed by Maharashtra.
• Rubber: Kerala is the largest producer.
• Oilseeds: groundnut (Gujarat is the largest producer), mustard, soybean (Madhya Pradesh is the largest producer) and sunflower.
• Pulses: Madhya Pradesh is the largest producer of pulses in India.
• Spices: Kerala (pepper), Karnataka, Andhra.

Green Revolution: started in the 1960s by Dr M.S. Swaminathan (with Norman Borlaug's high-yielding wheat varieties), it made India self-sufficient in food grains, concentrating first on wheat (Punjab, Haryana, western UP) and later on rice. The related terms are the White Revolution (Operation Flood, for milk, led by Verghese Kurien), the Yellow Revolution (oilseeds), the Blue Revolution (fish) and the Golden Revolution (fruits/horticulture). The main irrigation types in India are canals, wells/tube-wells and tanks; the largest irrigated area is under wells and tube-wells.

Key points to remember:

• Kharif crops are sown with the monsoon; Rabi crops are winter crops.
• Rice is the staple food; West Bengal is the largest producer of rice.
• Uttar Pradesh is the largest producer of wheat.
• Maharashtra is the largest producer of cotton, jowar and sugarcane comes second to UP.
• West Bengal is the largest producer of jute.
• Assam is the largest producer of tea in India.
• Karnataka is the largest producer of coffee.
• The Green Revolution made India self-sufficient in food grains.

Minerals are the backbone of modern industry. India is rich in many minerals, but they are unevenly distributed; the Chotanagpur plateau (Jharkhand, Odisha, West Bengal, Chhattisgarh) is the richest mineral belt of India.

Metallic minerals:

• Iron ore: India is among the world's leading producers. The main types are hematite and magnetite (best quality). The largest deposits are in Odisha (the largest producer — Sundargarh/Keonjhar), followed by Chhattisgarh (Bailadila, the best quality ore), Jharkhand and Karnataka (Kudremukh and Bellary-Hospet). The famous mines are in Singhbhum (Jharkhand), Mayurbhanj (Odisha) and Bailadila (Chhattisgarh).
• Manganese: essential for iron and steel; Odisha is the largest producer, followed by Karnataka and Madhya Pradesh.
• Bauxite (aluminium ore): Odisha is the largest producer (followed by Gujarat, Chhattisgarh); the main bauxite deposits are in the Amarkantak plateau, Maikala hills, the Panchpatmali plateau of Koraput (Odisha) and in Gujarat.
• Copper: Rajasthan (Khetri) is the leading producer; others are Madhya Pradesh and Jharkhand.
• Mica: Jharkhand is the leading producer; the Koderma-Gaya belt (Jharkhand-Bihar) is the world's leading mica belt.
• Gold: Karnataka is the leading producer (Kolar and Hutti mines).
• Other important minerals: limestone, dolomite, chromite (Odisha), and the radioactive mineral monazite (found on the Kerala coast, used for thorium).

Energy resources:

• Coal: India's most important source of commercial energy. The main types are anthracite (best), bituminous, lignite and peat. Jharkhand (Jharia, Bokaro), Odisha (Talcher), West Bengal (Raniganj, the oldest coal field) and Chhattisgarh (Korba) are the main producers; Jharia is the largest coal field of India. Lignite is mined mainly in Neyveli (Tamil Nadu).
• Petroleum: found mainly in the sedimentary rocks of the north-east (Digboi in Assam is the oldest oil field of India, and oil was struck there in 1889), Mumbai High (offshore, the largest oil field of India, in the Arabian Sea), and Gujarat (Ankleshwar, Kalol). The main oil refineries are at Digboi, Guwahati, Bongaigaon, Numaligarh (all in Assam), Mumbai, Barauni (Bihar), Koyali (Gujarat) and Kochi. Numaligarh refinery in Assam processes the crude from the Digboi and Duliajan (Naharkatia) fields.
• Natural gas: the main fields are in the Krishna-Godavari basin (offshore) and the north-east; the HBJ (Hazira-Bijapur-Jagdishpur) pipeline carries gas from Gujarat.
• Atomic minerals: thorium (in monazite sands of Kerala and Odisha beaches), uranium (Jaduguda in Jharkhand is the main uranium mine; also in Meghalaya, Andhra Pradesh and Rajasthan), and plutonium.
• Renewable energy: India has vast potential of solar (Rajasthan, Gujarat), wind (Tamil Nadu has the largest wind power capacity, followed by Gujarat), hydroelectric (the Himalayan states, Sikkim, Arunachal, Himachal) and biogas.

Key points to remember:

• The Chotanagpur plateau is the richest mineral belt of India.
• Odisha is the largest producer of iron ore, manganese and bauxite.
• Bailadila (Chhattisgarh) has the best quality iron ore; Kudremukh is in Karnataka.
• Khetri in Rajasthan is the leading copper mine.
• The Koderma-Gaya belt is the world's largest mica belt.
• Jharia is the largest coal field of India; Neyveli is famous for lignite.
• Digboi (Assam) is the oldest oil field of India; Mumbai High is the largest.
• Tamil Nadu has the largest wind power capacity in India.

Industry means the production of goods from raw materials. Industries are divided into agro-based, mineral-based, and modern (IT) industries. The main industrial regions of India are the Mumbai-Pune region, the Hooghly (Kolkata) region, the Delhi region, the Chotanagpur region and the Ahmedabad-Vadodara region.

Agro-based industries:

• Cotton textile industry: the oldest and one of the largest industries of India. It needs cotton, power and a large labour force and was historically concentrated in Maharashtra and Gujarat. Mumbai, Ahmedabad (called the 'Manchester of India' for its cotton mills), Coimbatore and Kanpur are important centres. Maharashtra is the largest producer of cotton textiles.
• Jute industry: concentrated in West Bengal, mainly along the Hooghly river; Kolkata is the world's largest jute manufacturing centre. It is now facing competition from Bangladesh.
• Sugar industry: India is the second largest producer of sugar in the world. Uttar Pradesh is the largest producer, followed by Maharashtra. In recent times the industry is shifting to Maharashtra and southern states because of the higher sucrose content of their cane.
• Tea, coffee and rubber industries: tea processing is important in Assam and West Bengal; coffee in Karnataka and Kerala.
• Silk and handloom industries: Karnataka (mulberry silk), Assam (muga, the golden silk found only in Assam, and eri and pat silk), and West Bengal.

Mineral-based industries:

• Iron and steel industry: the basic industry; it needs iron ore, coal, manganese and limestone. India is the second largest producer of crude steel in the world. The main steel plants are at Bhilai (Chhattisgarh), Durgapur and Burnpur (West Bengal), Rourkela (Odisha), Bokaro (Jharkhand), Jamshedpur (TISCO, the oldest, established by Jamshedji Tata in 1907), and the Vishakhapatnam steel plant (Andhra Pradesh).
• Aluminium industry: uses bauxite; the main plants are at Korba (Chhattisgarh) and Renukoot (Uttar Pradesh).
• Cement industry: needs limestone; the largest producer of cement is Rajasthan (which has the most cement plants), followed by Andhra Pradesh.
• Automobile industry: concentrated in Delhi-Gurugram, Mumbai-Pune, Chennai and Sanand (Gujarat). Maruti Suzuki (Gurugram), Tata Motors (Mumbai, Sanand) and Hyundai (Chennai) are important.
• Information Technology (IT) industry: the fastest growing industry; the main centres are Bengaluru (the 'Silicon Valley of India'), Hyderabad, Chennai, Pune, the National Capital Region (Gurugram, Noida) and Kolkata. Bengaluru is the largest IT hub.

Other important industries are the fertiliser industry, the petrochemical industry and the pharmaceutical industry (Hyderabad is called the 'pharma capital of India'). For competitive exams remember: the largest producer of jute goods is West Bengal; of steel, Jharkhand and Odisha are important; the first modern cotton mill was set up in 1854 in Bombay (Mumbai) by Cowasji Nanabhoy Davar.

Key points to remember:

• The cotton textile industry needs cotton and power; Mumbai and Ahmedabad are the traditional centres.
• The jute industry is concentrated along the Hooghly in West Bengal.
• Uttar Pradesh is the largest producer of sugar.
• TISCO at Jamshedpur (1907) is the oldest steel plant of India.
• Bhilai, Bokaro, Rourkela, Durgapur and Vishakhapatnam are public-sector steel plants.
• Rajasthan is the largest producer of cement.
• Bengaluru is the largest IT hub, called the Silicon Valley of India.
• The first modern cotton mill was set up in Mumbai in 1854.

Transport is the lifeline of a country's economy; it moves goods and people and helps trade. India has all types of transport — road, rail, water, air and pipelines.

Road transport: Roads are the most important means of transport in India because they reach the interior villages and are cheaper for short distances. India has one of the largest road networks in the world (about 63 lakh km). The National Highways carry most of the freight and passenger traffic though they form only a small part of the total road length. The main highways are the Golden Quadrilateral (connecting Delhi, Mumbai, Chennai and Kolkata), the North-South corridor (Srinagar to Kanyakumari) and the East-West corridor (Porbandar to Silchar). The longest national highway is NH 44 (Srinagar to Kanyakumari). Roads in India are classified as National Highways (NH), State Highways (SH), District Roads and Rural Roads.

Rail transport: The Indian Railways is one of the largest railway systems of the world. The first passenger train ran from Bombay (Bori Bunder) to Thane on 16 April 1853. Indian Railways is divided into zones; the headquarters of the zones are at Mumbai, Kolkata, Chennai etc. The main gauges are broad gauge (1.676 m), metre gauge and narrow gauge. The Vande Bharat Express is the fastest train of India; the Konkan Railway and the Brahmaputra bridge (Bogibeel, the longest rail-road bridge of India) are important projects. For Assam, the rail links connect it through the north (via New Jalpaiguri) and the Lumding-Silchar line connects the Barak valley.

Water transport: It is the cheapest mode for heavy goods. India has about 7,516 km of coastline with 13 major ports and about 200 minor ports. The major ports are Kandla (Deendayal) in Gujarat, Mumbai (the largest port of India), Jawaharlal Nehru Port (Nhava Sheva, the largest container port), Marmagao (Goa), New Mangalore, Kochi, Chennai (the oldest artificial harbour), Tuticorin, Visakhapatnam (the deepest port of India), Paradip, Haldia and Kolkata (a riverine port). Inland waterways: the National Waterways — NW1 is the Ganga (Allahabad-Haldia), NW2 is the Brahmaputra (Sadiya-Dhubri, which is very important for Assam), NW3 is the West Coast Canal, and NW4 is the Godavari-Krishna. The Suez Canal route is the main sea route used by Indian ships.

Air transport: Air India is the national carrier. The main international airports are at Delhi (IGI), Mumbai (Chhatrapati Shivaji Maharaj), Kolkata (Netaji Subhas Chandra Bose), Chennai, Bengaluru, Hyderabad, Kochi and Guwahati (Lokpriya Gopinath Bordoloi). Pawan Hans provides helicopter services, especially in the north-east and the islands.

Communication: India has one of the largest postal networks of the world (the first post office was set up by the British in 1837); the first telegraph line was opened in 1851. The telephone network and the internet (broadband) connect the whole country; the first satellite of India was Aryabhata (1975).

Trade: India exports petroleum products, gems and jewellery, textiles, engineering goods and software services, and imports crude petroleum, gold, machinery and electronic goods. The main trading partners are China, the USA and the UAE.

Key points to remember:

• The Golden Quadrilateral connects Delhi, Mumbai, Chennai and Kolkata.
• NH 44 (Srinagar to Kanyakumari) is the longest national highway.
• The first passenger train ran between Bombay and Thane on 16 April 1853.
• Mumbai is the largest port and Visakhapatnam the deepest port of India.
• NW2 (Brahmaputra, Sadiya-Dhubri) is the National Waterway important for Assam.
• The Bogibeel bridge is the longest rail-road bridge of India.
• Chennai has the oldest artificial harbour.
• India's first satellite Aryabhata was launched in 1975.

The study of population is called demography. India is the second most populous country of the world (after China) with a population of about 121 crore (1.21 billion) according to the Census of 2011. India conducts a census every ten years; the first complete census of India was held in 1881, and the latest census (2021) has been postponed.

According to the 2011 Census:

• Total population: about 121.09 crore, which is 17.7 per cent of the world's population.
• Decadal growth rate (2001–2011): about 17.7 per cent.
• Population density: about 382 persons per square km.
• Sex ratio: 940 females per 1,000 males.
• Literacy rate: about 74.04 per cent (male 82.14%, female 65.46%).
• The most populous state is Uttar Pradesh (about 19.96 crore), followed by Maharashtra and Bihar.
• The least populous state is Sikkim; among the Union Territories, Lakshadweep has the smallest population.
• The state with the highest population density is Bihar (1,106 per sq km), and the lowest density among states is in Arunachal Pradesh (17 per sq km).
• The state with the highest literacy is Kerala (about 94%), and the lowest is Bihar (about 61.8%).
• The sex ratio is the highest in Kerala (1,084) and the lowest in Haryana (879) among the states.
• The population of India is very unevenly distributed; the northern plains, the coastal regions and the delta areas are densely populated, while the deserts, high mountains and the thick forests of the north-east are thinly populated.

Important terms: Birth rate, death rate and migration determine the growth of population. Overpopulation creates problems of unemployment, poverty, food shortage and pressure on land; therefore family planning is promoted. The National Population Policy was announced in 2000 with the aim of stabilising the population by 2045. The average density of India is about 382 per sq km (2011). For Assam, the density is about 398 per sq km (2011) and its population is about 3.12 crore. The population of the north-eastern states is growing fast due to migration and high fertility, which is an important topic for the Assam examinations.

Key points to remember:

• India's population according to the 2011 census is about 121 crore.
• India conducts a census every ten years; the first complete census was in 1881.
• India is the second most populous country in the world.
• The population density of India (2011) is about 382 per sq km.
• The sex ratio (2011) is 940 females per 1,000 males.
• Uttar Pradesh is the most populous state of India.
• Kerala has the highest literacy rate and the highest sex ratio among the states.
• Bihar has the highest population density among the states.

India has a rich variety of animals and birds, and wildlife protection is an important subject for the Assam examinations. In India the wildlife is protected under the Wildlife (Protection) Act, 1972. National parks, wildlife sanctuaries and biosphere reserves have been created to protect animals, birds, plants and the natural environment. India has about 100 national parks and more than 500 wildlife sanctuaries; among the states, Madhya Pradesh has the largest number of national parks, and the Andaman and Nicobar islands also have many.

Some famous national parks of India:

• Jim Corbett National Park (Uttarakhand): the first national park of India (1936), famous for the Bengal tiger.
• Kaziranga National Park (Assam): famous for the one-horned rhinoceros; declared a UNESCO World Heritage Site in 1985. It lies on the bank of the Brahmaputra river. It is also home to the tiger, elephant, wild buffalo and swamp deer.
• Manas National Park (Assam): a UNESCO World Heritage Site and Project Tiger reserve, famous for the golden langur and the pygmy hog.
• Sundarbans National Park (West Bengal): famous for the Royal Bengal tiger and mangrove forests.
• Ranthambore (Rajasthan), Bandhavgarh and Kanha (Madhya Pradesh) are famous tiger reserves.
• Gir National Park (Gujarat): the only home of the Asiatic lion.
• Periyar (Kerala) and Nagarhole (Karnataka) are famous for elephants.
• Dachigam (Jammu & Kashmir) is famous for the Hangul (Kashmir stag).
• Keoladeo Ghana (Bharatpur, Rajasthan) is famous for birds.
• Valley of Flowers (Uttarakhand) is a World Heritage Site famous for alpine flowers.

Assam and the north-east have many protected areas. The national parks of Assam are Kaziranga, Manas, Nameri, Orang (Rajiv Gandhi Orang), Dibru-Saikhowa and Dehing Patkai. The famous wildlife sanctuaries of Assam are Pobitora (near Guwahati, famous for rhinos), Laokhowa, Burachapori, Pani Dihing, Garampani, Chakrashila (famous for golden langur) and Hoollongapar (Gibbon wildlife sanctuary, famous for the hoolock gibbon). The largest river island in the world, Majuli, is in the Brahmaputra. The projects for wildlife protection in India are Project Tiger (1973), Project Elephant (1992) and the Crocodile Breeding Project. The one-horned rhinoceros is found only in India and Nepal, and most of them live in Assam (Kaziranga has the largest number). The national aquatic animal of India is the Ganges river dolphin and the national animal is the tiger.

Biosphere reserves of India include the Sundarbans, the Gulf of Mannar, Nanda Devi, the Nilgiris, the Nokrek (Meghalaya), the Similipal, the Dehang-Dibang (Arunachal) and the Manas and Kaziranga areas of Assam. Ramsar sites are the wetlands of international importance; in Assam, Deepor Beel (near Guwahati) is a Ramsar site.

Key points to remember:

• Jim Corbett (Uttarakhand) is the first national park of India.
• Kaziranga is famous for the one-horned rhinoceros and is a World Heritage Site.
• Manas is a World Heritage Site famous for the golden langur and pygmy hog.
• Gir (Gujarat) is the only home of the Asiatic lion.
• Sundarbans is famous for the Royal Bengal tiger.
• Kaziranga has the largest number of one-horned rhinos in the world.
• Project Tiger started in 1973 and Project Elephant in 1992.
• Deepor Beel (Guwahati) is the Ramsar site of Assam.
• The six national parks of Assam are Kaziranga, Manas, Nameri, Orang, Dibru-Saikhowa and Dehing Patkai.

A disaster is a sudden event that causes great damage to life and property. India faces many natural disasters because of its geography — floods, cyclones, earthquakes, droughts, landslides, cloudbursts and heat waves. The National Disaster Management Authority (NDMA) was set up in 2005 after the Disaster Management Act of 2005.

Major natural disasters of India:

• Floods: the most common and most destructive disaster of India. They occur mainly in the northern plains (Ganga basin), the Brahmaputra basin and the coastal deltas. The rivers of Assam (Brahmaputra and Barak) cause floods almost every year, and river-bank erosion is a big problem in Assam. The flood-prone states are Assam, Bihar, Uttar Pradesh and West Bengal.
• Cyclones: violent storms that form over the warm sea. The Bay of Bengal side of India (Odisha, Andhra Pradesh, Tamil Nadu, West Bengal) suffers more cyclones than the Arabian Sea side. The super cyclone of Odisha in 1999 and Cyclone Amphan (2020) and Fani (2019) are famous examples. Bangladesh and the coast of India are the most cyclone-affected areas of the world.
• Earthquakes: sudden shaking of the ground caused by the movement of the earth's plates. The Himalayan region and the north-east are in earthquake zone V (the highest risk zone). The major earthquakes were at Latur (Maharashtra, 1993), Bhuj (Gujarat, 2001) and the great Assam earthquake of 1950 (magnitude 8.6). Assam and the north-east lie in the most earthquake-prone zone of India.
• Drought: shortage of rain over a long period; the areas of Rajasthan, Maharashtra and Karnataka suffer from drought. India's agriculture depends on the monsoon, so a weak monsoon causes drought.
• Landslides: common in the Himalayan states and the north-eastern hills.
• Tsunami: a huge sea wave caused by an earthquake under the sea. The Indian Ocean tsunami of 26 December 2004 destroyed the coastal areas of Tamil Nadu, Kerala, Andhra Pradesh and the Andaman and Nicobar islands.

Disaster management means the whole process of preparing for, responding to and recovering from a disaster. The Disaster Management Act was passed in 2005, the National Disaster Management Authority (NDMA) is headed by the Prime Minister, and the National Disaster Response Force (NDRF) is the special force for rescue work. In 2016 the Government of India announced the 'Sendai Framework' based approach; the National Disaster Management Plan follows it. For Assam, flood preparedness, the construction of embankments, early warning systems and the mock drill (Sikkim-style) education are the important parts of disaster management.

Key points to remember:

• Floods are the most common disaster of India; Assam, Bihar and UP suffer most.
• The Bay of Bengal coast suffers more cyclones than the Arabian Sea coast.
• The north-east and the Himalayas lie in earthquake zone V (highest risk).
• The great Assam earthquake occurred in 1950 (magnitude 8.6).
• The Disaster Management Act was passed in 2005 and NDMA was formed.
• The NDMA is headed by the Prime Minister; NDRF does the rescue work.
• The Indian Ocean tsunami of 2004 hit the Indian coast on 26 December.
• Drought is caused by the failure of the monsoon.

North-East India is connected to the rest of India only by a narrow corridor called the 'Chicken's Neck' (the Siliguri corridor in West Bengal). It consists of the seven sisters (Assam, Arunachal Pradesh, Nagaland, Manipur, Mizoram, Tripura and Meghalaya) and their brother Sikkim.

The main features of the north-east are the Brahmaputra valley, the Barak valley, the hills and the heavy rainfall. The region is surrounded by China (north), Myanmar (east), Bhutan and Bangladesh. The north-east has the highest rainfall in the world: Mawsynram (Meghalaya) and Cherrapunji are among the wettest places on earth; Mawsynram receives the highest rainfall in the world.

State-wise details:

• Assam: the gateway of the north-east, famous for tea, oil, silk and one-horned rhinos. The capital is Dispur (Guwahati). It is divided by the Brahmaputra valley and the Barak valley; Majuli is the largest river island in the world. The Brahmaputra enters Assam near Sadiya and leaves near Dhubri; the Barak flows through the Barak valley (Silchar).
• Arunachal Pradesh: the largest state of the north-east, also called the 'Land of the Dawn-lit Mountains'; the capital is Itanagar. It has the lowest population density (17 per sq km) among the states of India.
• Meghalaya: the 'Abode of Clouds', famous for Mawsynram and Cherrapunji rainfall and living root bridges; the capital is Shillong.
• Nagaland: the capital is Kohima; the Naga hills are here, and the Dzukou valley is famous.
• Manipur: the capital is Imphal; famous for the Loktak lake (the largest fresh-water lake of the north-east, with floating phumdis) and its classical dance.
• Mizoram: the capital is Aizawl; famous for its hills and bamboo.
• Tripura: the capital is Agartala; the smallest state of the north-east by area; the Ujjayanta palace and Tripura Sundari temple are famous.
• Sikkim: the capital is Gangtok; famous for Kanchenjunga (the third highest peak of the world), added to India in 1975.

Rivers of the north-east: the Brahmaputra (called Tsangpo in Tibet and Jamuna in Bangladesh; in India it is called Siang/Dihang in Arunachal and Brahmaputra in Assam), the Barak (becomes the Meghna in Bangladesh), the Dibang, Subansiri, Manas, Sankosh, Dhansiri and Kopili are its tributaries. The Barail range separates the Brahmaputra valley from the Barak valley. The Patkai hills, the Garo-Khasi-Jaintia hills, the Naga hills, the Mizo hills and the Mikir (Karbi) hills are the main hill ranges. The north-east has dense forests and the highest biodiversity of India; its wildlife includes the one-horned rhino, hoolock gibbon, golden langur and clouded leopard. The Diphu pass, the Bomdila pass and the Nathu La connect the region with the neighbouring countries.

Key points to remember:

• The Siliguri corridor ('Chicken's Neck') connects the north-east to India.
• The seven sisters plus Sikkim make the north-east.
• Mawsynram (Meghalaya) has the highest rainfall in the world.
• Arunachal Pradesh is the largest state of the north-east.
• Tripura is the smallest state of the north-east by area.
• Loktak lake (Manipur) is the largest fresh-water lake of the north-east.
• The Barail range separates the Brahmaputra and Barak valleys.
• The Brahmaputra is called Siang in Arunachal and Jamuna in Bangladesh.

For competitive examinations, quick revision of the 'extremes' of Indian geography is very important. Below is a summary table for memory:

Highest mountain peak of India and the world: Mount Everest (Nepal). The highest peak of India is K2 (Godwin-Austen) in the Karakoram range (now in Pakistan-occupied Kashmir), and the highest peak completely inside India is Kangchenjunga (on the Sikkim-Nepal border). The highest peak of the Eastern Ghats is Mahendragiri and of the Western Ghats is Anamudi (Kerala, 2,695 m). The highest peak of the Aravali range is Guru Shikhar (Mount Abu, Rajasthan).

Longest river of India: the Ganga (about 2,525 km within India); the longest river of the world is the Nile (in Africa). The longest tributary of the Ganga is the Yamuna, and the largest tributary (by volume) is the Ghaghara. The longest river of south India is the Godavari (the largest peninsular river). The longest river of the north-east is the Brahmaputra, and the Barak is the largest river of the Barak valley.

Largest state of India (by area): Rajasthan. The largest state by population: Uttar Pradesh. The largest state of the north-east: Arunachal Pradesh. The smallest state of India: Goa; the smallest Union Territory: Lakshadweep.

Largest plateau: the Deccan plateau. The largest delta: the Sundarbans delta (of the Ganga-Brahmaputra). The largest river island: Majuli (Assam, in the Brahmaputra). The largest lake of India: Wular (Jammu & Kashmir, fresh-water); the largest salt-water lake: Chilika (Odisha) and Sambhar (Rajasthan, the largest inland salt lake). The largest desert of India: the Thar (Rajasthan).

Highest dam: Tehri (Uttarakhand, on the Bhagirathi, the highest dam of India, height 260.5 m). The longest dam: Hirakud (Odisha, on the Mahanadi, the longest dam of the world, about 25.8 km). The largest dam (by storage) of India: Bhakra-Nangal (on the Satluj). The biggest multipurpose project: Bhakra-Nangal.

Highest waterfall: the Kunchikal falls (Karnataka) and the Jog falls (Karnataka, the highest plunge waterfall of India, on the Sharavati). The largest waterfall by volume: the Chitrakote falls (Chhattisgarh, the 'Niagara of India').

Highest rainfall place: Mawsynram (Meghalaya). The driest place: Jaisalmer (Rajasthan) region. The wettest place of India, historically, was Cherrapunji; now Mawsynram records the highest.

Deepest river valley and highest lake: the highest lake of India is the Gurudongmar lake (Sikkim); the largest fresh-water lake of the north-east is Loktak (Manipur).

Longest coast: Gujarat has the longest coastline among the states, and the total coastline of India is about 7,516 km. The deepest port: Visakhapatnam. The largest port: Mumbai.

The Tropic of Cancer (23.5° N) passes through eight states of India: Gujarat, Rajasthan, Madhya Pradesh, Chhattisgarh, Jharkhand, West Bengal, Tripura and Mizoram. The northernmost point of India is Indira Col; the southernmost point is Indira Point (Great Nicobar); the southernmost point of the Indian mainland is Kanyakumari. The standard meridian of India is 82.5° E, passing through Mirzapur (Uttar Pradesh).

Key points to remember:

• K2 is the highest peak of India; Kangchenjunga is the highest peak fully inside India.
• The Ganga is the longest river of India.
• The Godavari is the longest peninsular river.
• Rajasthan is the largest state and Goa the smallest state of India.
• Majuli is the largest river island of the world.
• Hirakud is the longest dam and Tehri the highest dam of India.
• Mawsynram has the highest rainfall in the world.
• The Tropic of Cancer passes through eight states of India.
• The standard meridian of India is 82.5° E (through Mirzapur).