Physical Geography of India: Location, Relief, and Drainage
India is a land of great physical diversity. Understanding its physical geography is foundational for UPSC and MPSC aspirants to grasp its climate, agriculture, and economic activities.
1. Location and Size
- India is located in the Northern and Eastern Hemispheres.
- Latitudinal Extent: 8°4’N to 37°6’N.
- Longitudinal Extent: 68°7’E to 97°25’E.
- Tropic of Cancer: (23.5°N) passes through eight Indian states: Gujarat, Rajasthan, Madhya Pradesh, Chhattisgarh, Jharkhand, West Bengal, Tripura, and Mizoram.
- Area: 3.28 million sq. km (7th largest country, 2.4% of world’s total geographic area).
- Standard Meridian: 82°30’E passing through Mirzapur (UP) is taken as the Standard Time for the whole country.
2. Physiographic Divisions
India can be divided into six major physiographic divisions:
A. The Himalayan Mountains
- Young fold mountains forming the northern border of India.
- Consists of three parallel ranges:
- Greater Himalayas (Himadri): Highest peaks like Mt. Everest, Kanchenjunga.
- Lesser Himalayas (Himachal): Famous for hill stations (Shimla, Mussoorie, Darjeeling).
- Outer Himalayas (Shiwaliks): Made of unconsolidated sediments.
B. The Northern Plains
- Formed by the interplay of three major river systems: the Indus, the Ganga, and the Brahmaputra.
- Highly fertile alluvial soil, densely populated.
- Divided into: Bhabar, Terai, Bhangar (older alluvium), and Khadar (newer alluvium).
C. The Peninsular Plateau
- A tableland composed of old crystalline, igneous, and metamorphic rocks.
- Consists of two broad divisions: The Central Highlands (Malwa plateau) and the Deccan Plateau.
- Bordered by the Western Ghats (continuous, higher) and Eastern Ghats (discontinuous).
D. The Indian Desert
- Lies towards the western margins of the Aravalli Hills (Thar Desert).
- Arid climate with low vegetation cover. Luni is the only large river in this region.
E. The Coastal Plains
- Western Coastal Plains: Narrow plains between the Western Ghats and the Arabian Sea (Konkan, Kannad, Malabar coasts).
- Eastern Coastal Plains: Wider and level plains between the Eastern Ghats and the Bay of Bengal (Northern Circars, Coromandel Coast). Form large deltas (Mahanadi, Godavari, Krishna, Kaveri).
F. The Islands
- Andaman and Nicobar Islands (Bay of Bengal): Larger in size, numerous, and scattered. Formed by volcanic activity and elevated submarine mountains.
- Lakshadweep Islands (Arabian Sea): Coral origin, smaller in area.
3. Drainage System
The flow of water through well-defined channels is known as ‘drainage’. Indian rivers are divided into two major groups:
A. Himalayan Rivers
- Perennial (have water throughout the year) as they receive water from rain as well as melted snow.
- The Indus System: Originates in Tibet near Lake Mansarovar. Tributaries: Jhelum, Chenab, Ravi, Beas, Satluj.
- The Ganga System: Originates as Bhagirathi from the Gangotri glacier. Major tributaries: Yamuna, Ghaghara, Gandak, Kosi, Son.
- The Brahmaputra System: Originates in Tibet. Known as Tsangpo in Tibet. Forms the world’s largest riverine island (Majuli) and delta (Sunderbans) along with Ganga.
B. Peninsular Rivers
- Seasonal, dependent on rainfall.
- West-flowing rivers: Narmada and Tapi. Flow through rift valleys and form estuaries.
- East-flowing rivers: Mahanadi, Godavari (Dakshin Ganga), Krishna, and Kaveri. Form large deltas on the east coast.
Conclusion
The varied relief features and extensive drainage networks make India highly resource-rich. The mountains act as water divides, plains are the granaries, and the plateau is a storehouse of minerals.