Indian Physical Geography: Peninsula, coasts, islands and rivers

The peninsular plateau, coastal plains and islands

The peninsular plateau is a triangle of old, hard rock, bounded by the Aravallis in the north-west, the Rajmahal hills and Shillong plateau in the east, and the Western and Eastern Ghats on its sides. The Narmada rift splits it into the Central Highlands (Malwa, Bundelkhand, Baghelkhand, Chota Nagpur) to the north and the Deccan plateau to the south. It slopes east, which is why most peninsular rivers flow to the Bay of Bengal.

Hills are the heart of these questions. Prelims 2014 paired hills with regions, starting with Cardamom Hills Coromandel Coast and Kaimur Hills Konkan Coast, then Mahadeo Hills with Central India and Mikir Hills with North-East India. Only the last two are right (option c): the Cardamom Hills are in the southern Western Ghats and the Kaimur Hills are the eastern end of the Vindhyas.

Prelims 2015 matched pilgrim towns with hills: Srisailam Nallamala Hills 2. Omkareshwar Satmala Hills 3. Pushkar Mahadeo Hills. Only Srisailam–Nallamala is right (option a); Omkareshwar is on a Narmada island in the Vindhya–Satpura belt and Pushkar is in the Aravallis. Prelims 2023 said that Amarkantak Hills are at the confluence of Vindhya and Sahyadri Ranges, that the Biligirirangan Hills are the easternmost part of the Satpura, and that the Seshachalam Hills are the southern end of the Western Ghats. None is correct (option d): Amarkantak joins the Vindhya and Satpura (Maikal), the Biligirirangan Hills link the Western and Eastern Ghats, and the Seshachalam Hills (Tirupati) are part of the Eastern Ghats.

Western Ghats (Sahyadri) Eastern Ghats

Continuity Continuous, broken only by passes (Thal, Broken into separate hills

Bhor, Pal) by the big east-flowing rivers

The western coastal plain is narrow and drowned by the sea: Kachchh and Kathiawar, then the Konkan (Mumbai to Goa), Kanara and the Malabar coast with its lagoons (kayals) and backwaters. Its rivers make estuaries, not deltas, and it has natural harbours (Mumbai, Mormugao, Kochi). The eastern coastal plain is wider and built by deltas of the Mahanadi, Godavari, Krishna and Kaveri: the Northern Circars in the north and the Coromandel coast in the south, with lagoons such as Chilika and Pulicat.

Mains 2023 asked: Comment on the resource potentials of the long coastline of India and highlight the status of natural hazard preparedness in these areas. Mains 2023 The long-used figure for the coastline is 7,516.6 km; a recent remeasurement on finer maps put it at about 11,098 km. Resources: fisheries, ports and shipping (Sagarmala), offshore oil and gas (Mumbai High, Krishna–Godavari), placer minerals (monazite in Kerala sands), salt, tidal and offshore wind energy, mangroves, and tourism. Preparedness: INCOIS early warnings, IMD cyclone forecasts that cut deaths sharply (Odisha, since 1999), the National Cyclone Risk Mitigation Project, shelters and the Coastal Regulation Zone rules; gaps remain in coastal erosion, sea-level rise and urban flooding.

India has two groups of islands. The Andaman and Nicobar Islands in the Bay of Bengal are the peaks of a drowned mountain chain, an extension of Myanmar’s Arakan Yoma; Barren Island there is India’s only active volcano. Lakshadweep in the Arabian Sea is made of coral atolls. Prelims 2014 asked which one of the following pairs of islands is separated from each other by the ‘Ten Degree Channel’: Andaman and Nicobar (option a); it runs between Little Andaman and Car Nicobar. Prelims 2017 asked which of the following is geographically closest to Great Nicobar: Sumatra (option a), across the Great Channel. Indira Point on Great Nicobar is India’s southernmost point.

Rivers, lakes and waterfalls

India’s rivers fall into two families: the Himalayan rivers, which flow all year, and the peninsular rivers, which depend on the monsoon. Most drain into the Bay of Bengal; the Narmada, Tapi, Mahi and Sabarmati drain into the Arabian Sea.

Prelims 2021 asked: With reference to the Indus river system, of the following four rivers, three of them pour into one of them which joins the Indus direct. That river is the Sutlej (option d): the Jhelum and Ravi join the Chenab, the Beas joins the Sutlej, and the Chenab and Sutlej together form the Panjnad, which meets the Indus near Mithankot in Pakistan. Prelims 2026 gave four clues. It has an antecedent drainage system. Prelims 2026 It flows through three countries, rises in the Tibetan Plateau and does not form distributaries. The river is the Sutlej (option c, provisional key), rising near Rakas Tal and cutting through the Himalaya at Shipki La.

The north-east is a frequent target. Prelims 2014 listed the Barak, Lohit and Subansiri and asked: Which of the above flows/flow through Arunachal Pradesh? Prelims 2014 Lohit and Subansiri (option b); the Barak rises in Manipur and flows through Mizoram and Assam into Bangladesh. Prelims 2017 asked about the Teesta. The source of river Teesta is the same as that of Brahmaputra is wrong (it rises in north Sikkim); the Rangeet rising in Sikkim and joining it is right; and it does not reach the sea at the border but joins the Brahmaputra in Bangladesh. So 2 only (option b).

Glaciers and sources: Prelims 2019 paired glaciers with rivers, including Milam Mandakini 4. Siachen Nubra 5. Zemu Manas. Bandarpunch–Yamuna, Bara Shigri–Chenab and Siachen–Nubra are right (option a); Milam feeds the Goriganga and Zemu the Teesta. Prelims 2019 also paired pilgrim towns with rivers: Pandharpur Chandrabhaga 2. Tiruchirappalli Cauvery 3. Hampi Malaprabha. The first two are right (option a); Hampi stands on the Tungabhadra. Prelims 2021 listed the Brahmani, Nagavali, Subarnarekha and Vamsadhara and asked: Which of the above rise from the Eastern Ghats? Prelims 2021 Nagavali and Vamsadhara (option b); the other two rise on the Chota Nagpur plateau.

Waterfalls form where rivers drop off a plateau edge or a fault. Prelims 2024 gave waterfall, region and river: Dhuandhar Malwa Narmada 2. Hundru Chota Nagpur Subarnarekha 3. Gersoppa Western Ghats Netravati. Only one row is right (option a): Hundru. Dhuandhar on the Narmada is at Bhedaghat near Jabalpur, not in Malwa, and Gersoppa (Jog) is on the Sharavati, not the Netravati.

Mains 2020 said: The interlinking of rivers can provide viable solutions to the multi-dimensional inter-related problems of droughts, floods, and interrupted navigation. Mains 2020 Critically examine. The National Perspective Plan (1980) proposes 30 links: 14 in the Himalayan component and 16 in the peninsular. The first to start is the Ken–Betwa link in Bundelkhand, whose foundation stone was laid in December 2024. Gains: water moved from surplus to deficit basins, irrigation, hydropower, inland navigation. Costs: huge expense, submergence of forests (part of Panna Tiger Reserve), displacement, changed river ecology and sediment flows to deltas, and disputes between states. Smaller steps such as watershed works and better irrigation efficiency often give more for less.