Revision: Geography >> India - Location, Relief and Drainage Social Science SSLC (English Medium) Class 10 Tamil Nadu Board of Secondary Education

• Subcontinent: A subcontinent is a part of a large continent, made up of several countries that form a large mass of land.

• Range: a vast landmass made of peaks, ridges, and mountains.
• Hills: A hill is a landform that extends above the surrounding terrain and a more rounded/mound shape than a distinct peak.

The total area drained by a river and its tributaries is known as a drainage basin.

A drainage system is an integrated system of tributaries and a trunk stream which collects and drains surface water into the sea, lake or some other body of water.

• Country Name: Republic of India; Capital: New Delhi.
• Hemispheres: India is located in the Northern and Eastern Hemispheres.
• Continent: India lies in the southern part of the Asian continent.
• Mainland Extent: India stretches from 8°4'N to 37°6'N latitudes and from 68°7'E to 97°25'E longitudes.
• Southernmost Point: Indira Point (6°45'N) is the southernmost tip of India, located in the Andaman and Nicobar Islands.

• The Himalayas are young fold mountains forming India’s Northern Mountain Wall, with three parallel ranges—Himadri, Himachal and Shiwalik.
• Himadri (Great Himalayas) is the highest and northernmost range, permanently snow-covered, with peaks like Mt. Everest, K2 and Kanchenjunga and major glaciers.
• Himachal (Middle Himalayas) lies south of Himadri, has rich vegetation, important ranges (Pir Panjal, Dhaula Dhar) and most hill stations.
• Shiwalik (Outer Himalayas) is the lowest and discontinuous range, with steep southern slopes, gentle northern slopes and average height of about 1000 m.
• Special Himalayan features include Doons (valleys), Bhabhar (porous plains), Terai (marshy belt) and fertile Khadar and Bhangar alluvial soils.

• The Himalayas are young fold mountains and one of the major mountain systems in Asia.
• They extend from the Pamir Knot in Tajikistan to eastern India (Jammu & Kashmir to Arunachal Pradesh).
• The Himalayas consist of parallel mountain ranges: the Siwaliks (youngest), the Lesser Himalayas, the Greater Himalayas (Himadri), and the Trans-Himalayas (oldest).
• The ranges are arranged south to north by age — youngest in the south, oldest in the north.
• The Himalayas are divided into Western (Kashmir), Central (Kumaun), and Eastern (Assam) Himalayas.

• The North Indian Plains lie between the Himalayas and the Peninsular Plateau, from Rajasthan to Assam.
• They were formed by alluvial deposits from the Indus, Ganga, and Brahmaputra rivers.
• These plains are flat, low-lying, and suitable for farming and settlements.
• They cover one-fifth of India’s area but support nearly half of the population.
• The plains are divided into Rajasthan, Punjab–Haryana, the Ganga Plains, and the Brahmaputra Plains.
• The Punjab–Haryana and Ganga Plains are fertile, irrigated, and densely populated.
• The Brahmaputra Plains are marshy and include Majuli Island; the Sunderbans Delta is the world’s largest.

• The Indian Peninsula lies south of the North Indian Plains and tapers toward the Indian Ocean.
• It is the oldest and largest physiographic division of India, mostly made of stable tableland.
• It is bounded by the Aravalli Range in the northwest and the Western and Eastern Ghats on the sides.
• The region includes many hill ranges and plateaus, such as the Vindhyas, Satpuda, and Aravalis.
• The Deccan Plateau is triangular and lies between the Western and Eastern Ghats, covering Maharashtra, Telangana, and Karnataka.
• The plateau is divided into Central Plateaus, Eastern Plateaus, Deccan Plateau, Kathiawar–Kutch region, and North-Eastern Plateau.
• This region is rich in minerals, has old rivers, and supports forests, farming, and mining.

• India has a coastline of approximately 7,500 km, extending along the eastern (Bay of Bengal) and western (Arabian Sea) sides of the Peninsula, meeting at Cape Comorin.
• The Western Coastal Plains are narrow, rocky, and indented, with short rivers forming estuaries; major ports include Mumbai and Kochi.
• The Eastern Coastal Plains are broad and flat, formed by deposition from major rivers like the Mahanadi, Godavari, Krishna, and Kaveri, leading to fertile deltas.
• Subdivisions: East coast – Northern Circars and Coromandel Coast; West coast – Gujarat, Konkan, Kanara, Malabar.
• The coastal plains are important for ports, minerals (like salt and monazite), and fisheries.

• India has two major island groups: the Lakshadweep Islands in the Arabian Sea and the Andaman & Nicobar Islands in the Bay of Bengal.
• The Lakshadweep Islands are mostly coral atoll islands, small, flat, and low in height, and lie off the Kerala coast.
• The Andaman & Nicobar Islands consist of many islands (about 265–300), mostly forested and hilly, and are separated by the Ten Degree Channel.
• Barren Island in the Andaman group has India’s only active volcano, and Indira Point in Great Nicobar is India’s southernmost point.
• These island groups are important for strategic location, biodiversity, and are surrounded by coral reefs and rich marine life.

• Indian rivers are divided into Himalayan (perennial) and Peninsular (seasonal) rivers.
• The Indus and Ganga systems drain the north; the Ganga forms a large delta with the Brahmaputra.
• Brahmaputra is called Tsang Po in Tibet, Dihang in India, and joins the Ganga in Bangladesh.
• Peninsular rivers flow east to the Bay of Bengal or west to the Arabian Sea; the Western Ghats form the water divide.
• West-flowing rivers include Narmada, Tapi, Mahi, Sabarmati, and Luni.
• East-flowing rivers include the Mahanadi, Godavari, Krishna, and Kaveri.
• Godavari is India’s second largest river system; Krishna and Kaveri are important for irrigation.