India is the seventh largest country in the world by area (3.29 million km2) and second most populous (1.4+ billion people). It is located in South Asia, bounded by the Himalayas in the north, the Indian Ocean in the south, the Arabian Sea in the west and the Bay of Bengal in the east.
Physical Divisions of India
1. Himalayan Mountains: Stretch 2,500 km from Indus gorge in the west to Brahmaputra gorge in the east. Three parallel ranges: Greater Himalayas (Himadri), Lesser Himalayas (Himachal), and Outer Himalayas (Shivalik). K2 (8,611m) is highest on India-Pakistan boundary. Kangchenjunga (8,586m) is the highest peak within India.
2. Northern Plains: Formed by alluvial deposits of the Ganga, Yamuna, Brahmaputra and their tributaries. World most extensive alluvial plain. Highly fertile, 2,400 km long. Divided into Punjab-Haryana plains (Punjab rivers), Ganga Plains (Ganga-Yamuna doab) and Brahmaputra valley.
3. Peninsular Plateau: Oldest geological unit. Mainly composed of Archaean gneisses and schists. The Vindhya and Satpura ranges divide the plateau. Deccan Plateau in the south, with Western Ghats and Eastern Ghats as boundaries.
4. Coastal Plains: Western Coastal Plains (narrow, 10-25 km) and Eastern Coastal Plains (wider, 100-130 km, called Coromandel Coast in south and Northern Circars in north).
5. Islands: Andaman and Nicobar Islands (Bay of Bengal, 572 islands) and Lakshadweep Islands (Arabian Sea, 36 islands, coral atolls).
Major Rivers
Himalayan rivers are perennial (flow year-round from glaciers and monsoon). Peninsular rivers are seasonal (depend on monsoon). Ganga (2,525 km, longest in India) rises from Gangotri glacier. Brahmaputra enters India in Arunachal Pradesh from Tibet. Narmada and Tapti flow westward into Arabian Sea through rift valleys, unlike most peninsular rivers flowing east.
Indian Monsoon
India receives most of its rainfall during the Southwest Monsoon (June-September). The monsoon is caused by the differential heating of land and sea, with the Inter-Tropical Convergence Zone (ITCZ) and the Tibetan Plateau playing critical roles. Average annual rainfall: ~118 cm, but varies from less than 10 cm in Rajasthan desert to over 1,000 cm in Cherrapunji/Mawsynram (world highest rainfall).
Agriculture
India is primarily an agricultural country. Kharif crops (sown June-July, harvested September-October): rice, cotton, sugarcane, groundnut. Rabi crops (sown October-November, harvested March-April): wheat, mustard, barley, peas. Zaid crops: grown between Rabi and Kharif seasons in summer months.
Green Revolution (1965-1978) introduced high-yielding variety (HYV) seeds, chemical fertilisers and irrigation, transforming India from food-deficit to food-surplus nation. Punjab and Haryana were the primary beneficiaries. White Revolution (Operation Flood) made India world largest milk producer.
Minerals and Energy
Coal: Jharia (Jharkhand) has the largest coalfield. Raniganj (WB) is the oldest coalfield. Petroleum: Mumbai High (offshore) is the major oilfield. Rajasthan (Barmer-Sanchore Basin) is growing rapidly. Dharwar and Gondwana rock systems are sources of iron ore and coal respectively.