Indian Geography

Location and extent

India lies between about 8°4′ N and 37°6′ N and 68°7′ E and 97°25′ E. The Tropic of Cancer passes through eight states: Gujarat, Rajasthan, Madhya Pradesh, Chhattisgarh, Jharkhand, West Bengal, Tripura and Mizoram.

Land neighbours: Pakistan, Afghanistan, China, Nepal, Bhutan, Myanmar and Bangladesh. Maritime neighbours include Sri Lanka and the Maldives. The Radcliffe Line faces Pakistan, the McMahon Line faces China in the east, and the Durand Line is the Afghanistan-Pakistan boundary.

Six physical divisions

1. The Himalayas — three parallel ranges: Himadri (Greater, with the highest peaks), Himachal (Lesser, with Pir Panjal, Dhauladhar and the valleys of Kashmir and Kullu) and Shiwaliks (Outer, with duns such as Dehradun).
2. The Northern Plains — built of alluvium: Bhabar (porous gravel at the foothills), Terai (marshy), Bhangar (older alluvium) and Khadar (newer, renewed each flood).
3. The Peninsular Plateau — the Central Highlands north of the Narmada and the Deccan Plateau south of it, with the Aravallis, Vindhyas, Satpuras and the black soil of the Deccan Traps.
4. The Coastal Plains — a wide eastern plain with deltas, and a narrow western plain with lagoons and backwaters.
5. The Thar Desert — western Rajasthan, with the seasonal Luni.
6. The Islands — Andaman and Nicobar (volcanic and tectonic, with India's only active volcano on Barren Island) and Lakshadweep (coral).

Peaks and passes: Kanchenjunga (Sikkim) is the highest peak within India; Nanda Devi (Uttarakhand), Nanga Parbat and K2 lie in the wider Himalayan system. Passes: Zoji La, Banihal, Rohtang, Shipki La, Nathu La, Bomdi La.

Rivers

The Indus system

Rises near Mansarovar; tributaries Jhelum, Chenab, Ravi, Beas and Sutlej. Under the Indus Waters Treaty (1960) India has unrestricted use of the eastern rivers — Ravi, Beas and Sutlej.

The Ganga system

The Ganga rises as the Bhagirathi from the Gangotri glacier and is joined by the Alaknanda at Devprayag. Left-bank tributaries: Ghaghara, Gandak, Kosi (the "sorrow of Bihar"). Right-bank: Yamuna (from Yamunotri), Son. The Yamuna receives the Chambal, Betwa and Ken. The Ganga and Brahmaputra together form the Sundarbans delta, the world's largest.

The Brahmaputra

Rises in Tibet as the Tsangpo, enters India in Arunachal Pradesh as the Dihang, and is joined by the Dibang and Lohit. It carries a huge silt load and braids across Assam, where Majuli is among the largest river islands.

Peninsular rivers

• East-flowing into the Bay of Bengal, with deltas: Mahanadi, Godavari (the largest peninsular river, "Dakshin Ganga"), Krishna, Kaveri.
• West-flowing into the Arabian Sea, through rift valleys and ending in estuaries: Narmada (Amarkantak) and Tapi.

Climate of India

India has a tropical monsoon climate. The Tropic of Cancer (23½° N) passes through the middle of the country, dividing it almost into two halves — a tropical south and a sub-tropical north. Even so, the whole country shows a monsoon rhythm: the rainy season and the dry season, with a reversal of wind direction between them.

Factors that shape the climate

The monsoon

The word monsoon comes from the Arabic mausim (season). The monsoon is a seasonal reversal of winds. In summer, the land heats up faster than the sea, creating a low pressure over north-west India, so moist winds blow from the sea to the land (south-west monsoon). In winter, the land cools faster; high pressure over the land causes dry winds from the land to the sea (north-east monsoon).

Mechanism (modern view)

• The shift of the Inter-Tropical Convergence Zone (ITCZ) northward over the Ganga plain in summer; the south-east trade winds of the southern hemisphere cross the equator and turn right (Coriolis force) into the south-west monsoon.
• The Tibetan plateau heats up strongly, drawing in the monsoon; the Tropical Easterly Jet stream over the peninsula assists the "burst" of the monsoon.
• Normal date of onset over the Kerala coast: about 1 June; it covers the whole country by about 8 July (a recent shift to 8 July from 15 July was made in the IMD's normals); the withdrawal begins in north-west India in September.
• The monsoon has two branches: the Arabian Sea branch (rains on the Western Ghats first; Mumbai; passes to Gujarat and Rajasthan with little rain) and the Bay of Bengal branch (enters via the north-east and turns west along the Himalayan foothills, giving heavy rains to the Ganga plain).
• Breaks in the monsoon: dry spells within the rainy season.
• Mango showers (pre-monsoon showers in Kerala and Karnataka, help mangoes ripen), Kalbaisakhi (Norwesters, thunderstorms in Bengal and Assam in April–May), Loo (hot, dry wind in the north-west plains in summer), Blossom showers (coffee flowers in Karnataka).
• El Niño (warming of the Pacific off Peru) usually weakens the Indian monsoon and causes drought; La Niña usually strengthens it. The Indian Ocean Dipole (IOD) — a positive phase helps the monsoon.

The four seasons

Rainfall distribution

• Very heavy (over 250 cm): the Western Ghats windward slopes, the north-eastern states (Meghalaya, Assam hills), the sub-Himalayan West Bengal and the Andaman & Nicobar Islands.
• Heavy (200–250 cm), moderate (100–200 cm): parts of the Ganga plain, the east coast, Odisha and Chhattisgarh.
• Low (50–100 cm): the Deccan interior, eastern Rajasthan, Punjab, Haryana, western UP.
• Very low (< 50 cm): west Rajasthan (Thar), Ladakh, parts of Gujarat, and Karnataka's rain-shadow area; Jaisalmer is among the driest places.
• Average annual rainfall of India: about 117 cm. Rainfall is highly variable and depends on the monsoon.
• The Andaman & Nicobar Islands get the earliest monsoon rains (about mid-May). The coldest inhabited place in India is Dras (Ladakh); Leh is a cold desert. The hottest places are in the Thar and the plains (Sri Ganganagar, Banda and others).
• Climate classification: Köppen — India has climate types such as Am (tropical monsoon), Aw (tropical savanna), BSh (semi-arid), BWh (arid), Cwg (humid sub-tropical) and E (polar/mountain). Koeppen's system is the one used in exams.

A note on figures. Production rankings and totals change every year. The leading states and ranks below reflect the position in recent years; use the current Economic Survey or the Ministry of Agriculture's advance estimates for exact numbers.

Agriculture in India

Agriculture employs about 45 % of the workforce (roughly) but contributes a much smaller share (about 15–18 %) of the GDP. The main features: dependence on the monsoon, small holdings, and a mix of subsistence and commercial farming.

Types of farming

Cropping seasons

Major crops

Revolutions in agriculture

Irrigation

• Sources: wells and tube wells (the largest share of the net irrigated area; mainly in the Ganga plain and Punjab), canals (Punjab, Haryana, UP, and the deltas), tanks (peninsular India — Tamil Nadu, Andhra), others.
• Multipurpose river-valley projects and micro-irrigation (drip and sprinkler) save water; the Pradhan Mantri Krishi Sinchayee Yojana (PMKSY) ("Har Khet Ko Pani"; "More Crop per Drop").
• Fertilisers: urea (largest use), DAP, MOP. Minimum Support Price (MSP) is set by the government on the recommendation of the CACP (Commission for Agricultural Costs and Prices). NABARD finances agriculture and rural development. e-NAM is an online trading platform for agricultural produce.