India's Drainage Systems and Mineral Resources

India's rivers and its mineral deposits sit on the same geological base. Most metallic minerals occur in the old crystalline rocks of the peninsular plateau, and the rivers draining off that same plateau, alongside the Himalayan rivers, have been dammed for decades to store and distribute water. UPSC draws heavily on both the Water Resources and the Mineral and Energy Resources chapters, and it tests named rivers, named dams and named mining belts, not general definitions.

India's River Basins

India gets about 4,000 cubic km of water a year from precipitation. Of the 1,869 cubic km available from surface flow and replenishable groundwater, only about 60 per cent, roughly 1,122 cubic km, can actually be put to beneficial use once topography and other constraints are accounted for. There are over 10,360 rivers and tributaries longer than 1.6 km in the country.

A single fact worth remembering precisely: the Ganga, Brahmaputra and Barak basins together account for only about one-third of India's total area, but because their catchments sit in the highest-rainfall zones, they hold 60 per cent of the country's total surface water resources. Much of south India's river flow, by contrast, in the Godavari, Krishna and Kaveri, has already been harnessed, while the Brahmaputra and Ganga basins still have large untapped potential.

NCERT's river-basins map splits the country into west-flowing and east-flowing systems. The Indus, Ganga, Brahmaputra and Barak basins, along with the Narmada and Tapi, are grouped on the west-flowing and northern-plains side; the Mahanadi, Godavari, Krishna, Pennar and Kaveri flow east into the Bay of Bengal. Two further groups get their own label: the small west-flowing rivers of Kachchh, Saurashtra and the Luni, and the west-flowing rivers south of the Tapi.

Multipurpose Projects and Water Demand

India's water demand is dominated by irrigation: agriculture accounts for 89 per cent of surface water use and 92 per cent of groundwater use, against just 2 per cent and 5 per cent for industry. To meet this, the Five Year Plans took up a set of multipurpose river valley projects that UPSC names directly: Bhakra-Nangal (Sutlej), Hirakud (Mahanadi), the Damodar Valley project (Damodar), Nagarjuna Sagar (Krishna), and the Indira Gandhi Canal Project. Punjab, Haryana and western Uttar Pradesh owe the Green Revolution's success largely to assured irrigation from projects and wells built on this base.

Where the Water Stress Actually Shows Up

Heavy reliance on wells and tubewells, 76.1 per cent of Punjab's net irrigated area and 51.3 per cent of Haryana's, has driven a real decline in the water table in both states. Over-extraction has a second, less obvious cost: it has raised fluoride concentration in groundwater in Rajasthan and Maharashtra, and raised arsenic concentration in parts of West Bengal and Bihar. On surface water, the Central Pollution Control Board's monitoring identifies the Yamuna between Delhi and Etawah as the most polluted river stretch in the country, ahead of the Sabarmati, the Gomti and the Ganga at Kanpur and Varanasi.

River Interlinking: The National Perspective Plan

The imbalance the sections above describe, most of the country's surface water sitting in the Ganga, Brahmaputra and Barak basins while peninsular rivers like the Krishna and Kaveri are already fully harnessed, is exactly what India's river interlinking programme was designed to fix. The government's answer was the National Perspective Plan (NPP), prepared in 1980 by the then Ministry of Irrigation together with the Central Water Commission, aimed at transferring water from basins with a surplus to basins with a deficit. Implementation was handed to a dedicated body, the National Water Development Agency (NWDA), set up in 1982 and now under the Ministry of Jal Shakti.

The NPP has two components. The Himalayan Rivers Development Component proposes storage reservoirs on Ganga and Brahmaputra tributaries, including sites in Nepal and Bhutan, to move the eastern rivers' surplus flow westward and link the Himalayan river systems to each other. The Peninsular Rivers Development Component works within the south: it proposes a chain of storages linking the Mahanadi, Godavari, Krishna and Kaveri, connects west-flowing rivers south of the Tapi, plans a Ken-Chambal link, and looks at diverting some west-flowing Western Ghats rivers eastward. Between the two components, NWDA has identified 30 links in total, 14 under the Himalayan component and 16 under the Peninsular component, though only a handful have moved past the survey and approval stage since 1980.

One Peninsular link is already operational, and it is the one UPSC has already asked about directly: the Pattiseema lift irrigation scheme, commissioned in 2015, pumps Godavari water into the Krishna's channel near Vijayawada, linking the two rivers the National Perspective Plan itself names as one of its Peninsular targets.

The Ken-Betwa Link Project

India's first fully sanctioned interlinking project under the NPP is the Ken-Betwa Link Project, part of the Ken-Chambal link inside the Peninsular component. Both the Ken and the Betwa are tributaries of the Yamuna; the Ken carries a monsoon surplus while the Betwa's basin, sitting across the drought-prone Bundelkhand region, runs short every year. The project moves Ken water into the Betwa through a roughly 221 km canal fed by the Daudhan Dam, a 77 metre high structure built on the Ken inside Madhya Pradesh, and it touches districts of both Madhya Pradesh (Chhatarpur, Panna, Tikamgarh and Damoh among them) and Uttar Pradesh (Jhansi, Banda, Lalitpur and Mahoba).

Its stated objectives are annual irrigation for about 10.62 lakh hectares, drinking water for roughly 62 lakh people, and 103 MW of hydropower plus 27 MW of solar power. The Union Cabinet approved its funding and implementation on 8 December 2021, at a cost of Rs 44,605 crore; the Prime Minister laid the foundation stone at Khajuraho on 25 December 2024, the 100th birth anniversary of Atal Bihari Vajpayee, whose government had first put river interlinking on the national agenda in the early 2000s.

The project's most-cited environmental cost sits inside the Daudhan reservoir's own submergence zone: close to 6,000 hectares of the Panna Tiger Reserve, roughly a tenth of the reserve's core, critical tiger habitat, will go under water, on top of an indirect loss from habitat fragmentation around the new shoreline. A national infrastructure project cutting directly into a tiger reserve is precisely the kind of specific, sourced detail UPSC likes to turn into a statement-based question.

The Case For and Against River Interlinking

Supporters of interlinking point to the same regional imbalance opened this note: moving water from a flood-prone basin to a drought-prone one should, on paper, cut both problems at once, expand irrigated area, and add hydropower capacity without needing a single new river. Bundelkhand's chronic water stress, the reason the Ken-Betwa project exists at all, is the case usually made in favour of the whole programme.

Critics raise objections that recur across nearly every proposed link. Ecological disruption comes first: damming and diverting a river changes downstream flow, silt deposition and estuarine salinity, with real consequences for the fisheries and mangroves that depend on that flow, and Ken-Betwa's own submergence of tiger habitat is the clearest current example. Interstate water-sharing disputes follow close behind: a link only works if both a surplus state and a deficit state agree on how much water genuinely counts as surplus, and India already runs long tribunal disputes, the Kaveri dispute among them, over rivers nobody is even proposing to interlink yet. Displacement is a third recurring objection: reservoirs like the Daudhan dam submerge inhabited land as well as forest, and resettlement has been a slow, contested part of nearly every major dam project in India. A fourth objection is cost and scale: NWDA's own 30-link programme, priced across decades, dwarfs any single approved project, and most links remain on paper more than four decades after the NPP was drawn up.

For the exam, treat river interlinking as a live, contested policy area rather than a finished achievement: know the NPP's two components and their link counts, the one operational Peninsular link (Pattiseema, Godavari-Krishna), the one funded and foundation-laid project (Ken-Betwa), and the specific environmental cost attached to each.

The Three Mineral Belts

NCERT groups most of peninsular India's minerals into three broad belts, with a separate Himalayan belt alongside them.

• North-Eastern Plateau belt: Chhotanagpur (Jharkhand), the Odisha plateau, West Bengal and parts of Chhattisgarh. Iron ore, coal, manganese, bauxite and mica all occur together here, which is exactly why India's iron and steel industry clustered in this belt.
• South-Western Plateau belt: Karnataka, Goa, and the Tamil Nadu and Kerala uplands. Rich in ferrous metals and bauxite, but it lacks coal deposits except for Neyveli lignite. Kerala has monazite, thorium and bauxite clay; Goa has iron ore.
• North-Western belt: along the Aravalis in Rajasthan and part of Gujarat, tied to the Dharwar rock system. Copper and zinc are the major minerals; Rajasthan also supplies building stone (sandstone, granite, marble), gypsum and Fuller's earth, while Gujarat has petroleum and salt.
• A separate Himalayan belt carries copper, lead, zinc, cobalt and tungsten on both its eastern and western flanks. Offshore, petroleum comes from Mumbai High and the sedimentary basins of Assam and Gujarat, with newer reserves found in the Krishna-Godavari and Kaveri basins.

Named Deposits Worth Remembering

• Iron ore: over 95 per cent of reserves sit in Odisha, Jharkhand, Chhattisgarh, Karnataka, Goa, Telangana, Andhra Pradesh and Tamil Nadu. Named mines: Gurumahisani, Sulaipet, Badampahar and Bonai in Odisha; Noamundi and Gua in Jharkhand; Bailadila and Dalli-Rajhara in Chhattisgarh; Ballari and Kudremukh in Karnataka.
• Coal: the Gondwana coalfields of the Damodar valley (the Jharkhand-Bengal belt) hold India's largest reserves; Jharia (Jharkhand) is the single largest coalfield and the country's main coking-coal source, and Raniganj (West Bengal) was where coal mining in India began. Other major fields sit at Bokaro and Giridih (Jharkhand), Korba (Chhattisgarh), Talcher (Odisha, the highest geological reserves of any single field), Singrauli (Madhya Pradesh) and Singareni (Telangana, in the Godavari valley).
• Manganese: Madhya Pradesh's Balaghat-Chhindwara-Nimar-Mandla-Jhabua belt, and Karnataka (Dharwar, Ballari, Chikkamagaluru).
• Bauxite: Odisha is the largest producer, led by Kalahandi and Sambalpur.
• Copper: Singhbhum (Jharkhand), Balaghat (Madhya Pradesh), and Jhunjhunu and Alwar (Rajasthan).
• Mica: Jharkhand's belt in the lower Hazaribagh plateau supplies the bulk of production; Andhra Pradesh's Nellore district produces the best quality; Rajasthan's belt runs about 320 km from Jaipur to Bhilwara and around Udaipur.

The Exam Trap: Major versus Minor Minerals

This distinction is a UPSC favourite precisely because it is a legal category, not a geological one. Under Section 3(e) of the Mines and Minerals (Development and Regulation) Act, 1957, "minor minerals" are defined by name: building stones, gravel, ordinary clay and ordinary sand (other than sand used for prescribed purposes), plus anything else the Central Government chooses to notify as a minor mineral. Everything else, including big-ticket minerals like iron ore, bauxite, manganese, coal and petroleum, counts as a major mineral by default. The Act never defines "major mineral" on its own terms.

The consequence UPSC tests: minor minerals are regulated by State Governments (rules, royalty rates, leases, under Section 15 of the Act), while major minerals fall under the Union Government through the Ministry of Mines. A mineral's economic value has nothing to do with which list it sits on. It is purely a question of what Parliament, or a Central Government notification, has named.

A related, genuinely testable policy change sits alongside this distinction: the Mines and Minerals (Development and Regulation) Amendment Act, 2015 replaced the old discretionary, first-come-first-served grant of mining leases for major minerals with a mandatory auction, competitive bidding, for identified minerals such as bauxite, iron ore, limestone and manganese ore. The same amendment created the District Mineral Foundation (DMF), funded from a share of mining revenue to benefit people and areas affected by mining, and the National Mineral Exploration Trust (NMET), funded by a 2 per cent levy on mining leaseholders to finance fresh exploration. Minor minerals, still regulated by the states, sit outside the auction mandate; each state continues to set its own allocation rules for those.

Quick revision points

• Ganga + Brahmaputra + Barak basins: about one-third of India's area, 60 per cent of its surface water.
• Multipurpose projects to know by river: Bhakra-Nangal (Sutlej), Hirakud (Mahanadi), Damodar Valley (Damodar), Nagarjuna Sagar (Krishna), Indira Gandhi Canal.
• Agriculture uses 89 per cent of surface water and 92 per cent of groundwater in India; the Yamuna (Delhi to Etawah) is the country's most polluted river stretch.
• River interlinking: the National Perspective Plan (1980), run by the NWDA (set up 1982), has two components, Himalayan (14 links) and Peninsular (16 links), 30 links in all. Pattiseema (2015) already links the Godavari and Krishna.
• Ken-Betwa Link Project: India's first sanctioned interlinking project, Ken to Betwa, Madhya Pradesh and Uttar Pradesh, built around the Daudhan Dam. Cabinet approval 8 December 2021; foundation stone laid 25 December 2024. Submerges close to 6,000 hectares of the Panna Tiger Reserve, roughly a tenth of its core critical tiger habitat.
• Interlinking arguments: for, drought and flood mitigation plus added irrigation and hydropower; against, ecological disruption, interstate water-sharing disputes, and displacement.
• Three mineral belts: North-Eastern Plateau (iron, coal, manganese, bauxite, mica together), South-Western Plateau (ferrous metals and bauxite, almost no coal), North-Western (copper, zinc, building stone, along the Aravalis).
• Odisha leads bauxite and iron ore reserves; Madhya Pradesh and Karnataka lead manganese; Jharkhand's Singhbhum leads copper; Jharia is India's largest coalfield.
• Minor minerals (building stones, gravel, ordinary clay, ordinary sand, plus anything Centre-notified) are regulated by the States; every other mineral is a major mineral, regulated by the Union and, since the 2015 MMDR Amendment, allocated by auction.

Once the river basins, the named dams, the interlinking programme and the mineral belts are fixed in place, practise the statement-based and matching-pairs questions UPSC builds around them.