Chapter 7 — Resources of India

In everyday speech we call coal, water or forests resources. But a resource in geography is not the thing itself; it is the usefulness of the thing to human beings. A resource is anything in the environment that can be used to satisfy a human need, provided that we have the technology to use it and that using it is acceptable to society. The geographer Zimmermann put it in a famous sentence: resources are not, they become. Coal lay in the ground for 300 million years and was a black rock; it became a resource only when people learnt to burn it for heat and then to drive steam engines. Petroleum was a nuisance that spoilt wells until the internal combustion engine was invented. Uranium was a curiosity until the nuclear reactor. The wind blew over Tamil Nadu for ever, but it became a resource when wind turbines were installed.

Three things therefore combine to make a resource:

• Nature supplies the material or the force: the ore, the river, the sunlight, the soil.
• Technology is the knowledge and the tools that let us use it: the blast furnace, the dam, the solar cell.
• Human need or demand gives it value: without a market or a use, even a rich deposit is left in the ground.

This idea has several consequences. First, the same object can be a resource for one society and not for another. Bauxite is a resource for a country with aluminium smelters and cheap electricity, and only red earth for one without. Second, resources change with time. Whale oil was a major fuel in the nineteenth century and is nothing today; silicon sand was worthless and is now the basis of the electronics industry. Third, resources can be created by people: the fertility of a well-manured field, the skill of a trained workforce, the road that opens a valley are all human-made resources. Fourth, a resource has a functional and a cultural side — a cow is a draught animal to a farmer, a source of milk to a dairy, and a sacred animal to many; how it is used depends on culture.

Resources are also the base of economic development. Countries rich in resources but poor in technology, like many in Africa, export raw materials cheaply; countries poor in resources but rich in technology, like Japan, import materials and grow rich by processing them. India is fortunate in having both a wide resource base — fertile plains, minerals, a long coast, tropical sunshine — and a growing technological capacity. The task of the chapter is to see what those resources are, where they lie and how they should be used.

Resources are classified in several ways, each useful for a different purpose.

1. By origin. Natural resources are provided by nature: land, soil, water, forests, minerals, sunlight. Human-made resources are created by people from natural ones: roads, buildings, machines, dams, and also knowledge and institutions. Human resources are people themselves — their number, health, skill and education. A country with a large, healthy and educated population has a great resource in its people.

2. By renewability. Renewable resources are replaced by nature within a human lifetime or are inexhaustible: sunlight, wind, water in the hydrological cycle, forests and fish if not over-used, soil if not eroded. Non-renewable resources took millions of years to form and are not replaced once used: coal, petroleum, natural gas, iron ore, copper and all other minerals. Some, like metals, can be recycled; fossil fuels cannot. Forests and fish are renewable only if the rate of use stays below the rate of regrowth; over-use makes a renewable resource behave like a non-renewable one.

3. By nature. Biotic resources come from living things: forests, crops, animals, fish, and also coal and petroleum since they were formed from ancient plants and animals. Abiotic resources are non-living: land, water, air, minerals, sunlight.

4. By exhaustibility. Inexhaustible resources cannot be used up whatever we do: solar energy, wind, tides, air. Exhaustible resources can be used up: minerals, fossil fuels, and living resources if abused.

5. By stage of development. Potential resources are known to exist but are not yet used, usually for lack of technology or money: the wind of Gujarat before turbines, the tidal power of the Gulf of Khambhat, the uranium under the Meghalaya hills. Developed or actual resources are surveyed, measured and in use: the coal of Raniganj, the iron ore of Odisha. Reserves are the part of the known stock that can be extracted with present technology at a profit. Stock is everything that exists, including what we cannot yet use — the hydrogen in sea water is a stock, not a reserve.

6. By ownership. Individual resources such as a farmer's field; community resources such as a village pond or grazing land; national resources such as minerals, forests and the territorial sea up to 12 nautical miles, all owned by the nation; and international resources such as the open ocean beyond 200 nautical miles and Antarctica, which no country owns.

7. By distribution. Ubiquitous resources are found everywhere — air, sunlight; localised resources are found only in certain places — iron ore, petroleum, gold. Localised resources shape the map of industry and trade.

Land is the most basic resource: every human activity — farming, housing, industry, roads, forests — needs a surface to stand on, and the supply of land is fixed. India has about 32.87 lakh square kilometres, 2.4 per cent of the world's land, but supports about 17.7 per cent of the world's population. Land per person is therefore very small, about 0.24 hectares, and every hectare must be used wisely.

Land use in India. Of the area for which records exist, about 46 per cent is net sown area, the highest proportion of any large country, made possible by the vast alluvial plains. About 22 per cent is under forest, well below the 33 per cent recommended by the National Forest Policy. About 5 per cent is put to non-agricultural use — towns, roads, railways, canals — and this share grows every year as cities spread over farmland. About 3 per cent is pasture, very little for the world's largest cattle population. The rest is barren and unculturable land (deserts, rocky hills), culturable waste that could be farmed with effort, and fallow land left to rest.

The relief of India shapes its land use. The Northern Plains, flat and alluvial, are the most intensively cultivated land in the world. The Peninsular plateau is rich in minerals and, on the black soils of the Deccan, in cotton. The Himalaya gives forests, pasture and water but little farmland. The coastal plains grow rice and coconut and hold the ports.

Problems of land. Soil erosion by water and wind, especially in the Chambal ravines and the Shiwalik foothills; waterlogging and salinity in over-irrigated canal areas of Punjab and Haryana; desertification on the fringes of the Thar; loss of farmland to cities and industry; fragmentation of holdings into tiny plots; and pollution from industrial waste and excess chemicals.

Soil as a resource. Soil is the thin living layer of weathered rock and humus on which all crops depend. India's main soil types are: alluvial soil of the northern plains and deltas, the most fertile and most extensive, growing rice, wheat, sugarcane and jute; black (regur) soil of the Deccan lava region, formed from basalt, rich in clay, holds moisture and is ideal for cotton; red and yellow soil of the eastern and southern plateau, formed from crystalline rocks, poor in nitrogen, coloured by iron; laterite soil of the wet plateau margins including Purulia, Bankura and Midnapore, leached by heavy rain, hard and poor but good for cashew and tea; desert soil of Rajasthan, sandy and saline; mountain soil of the Himalaya, thin and rich in humus, good for tea, fruit and spices; and peaty and marshy soil of the Sundarbans and Kerala backwaters.

Soil conservation is needed because soil takes centuries to form and can be lost in one monsoon. Contour ploughing and bunding, terracing on slopes, strip cropping, shelter belts of trees against wind, afforestation, control of overgrazing, check dams in gullies and crop rotation with pulses all protect and rebuild the soil.

Forests are a renewable, biotic resource of the first importance. India has about 7.1 lakh square kilometres of forest cover, roughly 21–22 per cent of its area, well short of the one-third that the National Forest Policy of 1988 recommends for ecological balance. Forest cover is highest in the north-eastern states (Mizoram, Arunachal Pradesh), Madhya Pradesh, Chhattisgarh and Odisha, and lowest in Punjab, Haryana and Rajasthan. West Bengal has about 16 per cent, concentrated in the Darjeeling and Jalpaiguri hills, the Sundarbans and the south-western districts.

Types of forest by climate.

• Tropical evergreen forests grow where rain exceeds 200 cm: the Western Ghats, the north-east and the Andamans. Trees are tall, dense and never leafless; rosewood, mahogany, ebony and rubber grow here.
• Tropical deciduous (monsoon) forests, the most widespread, grow with 70–200 cm of rain across the peninsula, the Shiwaliks and West Bengal's plateau fringe. Trees shed leaves in the dry season; sal, teak, sandalwood, shisham and bamboo are the wealth of these forests.
• Thorn and scrub forests grow with less than 70 cm in Rajasthan, Gujarat and the rain-shadow Deccan: acacia (babul), khejri, date palm, cactus.
• Montane forests of the Himalaya change with height: sal and bamboo at the foot, oak and chestnut, then pine, deodar, fir and spruce, then alpine meadows.
• Mangrove (tidal) forests grow in the deltas; the Sundarbans, the largest mangrove forest in the world, is named after the sundari tree and also has gewa, garan and hental.

Uses of forests. Direct uses are timber for building and furniture, firewood which is still the main fuel of rural India, pulp for paper, bamboo, resin, lac, gum, honey, medicinal herbs, tendu leaves for bidis and fodder. Indirect uses are even more valuable: forests hold the soil against erosion, regulate the flow of rivers and the recharge of groundwater, moderate climate and rainfall, absorb carbon dioxide and release oxygen, shelter wildlife, and support the livelihood of tribal communities. Mangroves break cyclone surges and nurse fish.

Problems. Deforestation for farming, dams, mines and roads; illegal felling; overgrazing; forest fires; and shifting (jhum) cultivation in the north-east. Between 1950 and 1980 India lost about 40 lakh hectares of forest.

Conservation. The Forest Conservation Act of 1980 requires central permission to divert forest land. Social forestry plants trees on village and roadside land for fuel and fodder; agro-forestry mixes trees with crops; Joint Forest Management, begun at Arabari in West Midnapore in 1972, shares protection and profit with village committees and has become a national model. The Chipko movement of 1973 in Uttarakhand, in which villagers hugged trees to stop felling, showed the power of the people. Wildlife sanctuaries, national parks and Project Tiger (1973, with the Sundarbans as one of the first reserves) protect forests together with their animals. Vana Mahotsava each July encourages planting.

Water is a renewable resource, endlessly recycled by the hydrological cycle, but its supply in a given place and season is limited, and India, with 4 per cent of the world's fresh water and 17.7 per cent of its people, feels that limit sharply. India receives about 4,000 billion cubic metres of rain a year, of which about 1,869 billion cubic metres flow in rivers and about 1,123 billion cubic metres can be used — 690 from surface water and 433 from groundwater.

Sources. Surface water is held in rivers, lakes, ponds and reservoirs. The Himalayan rivers — Ganga, Brahmaputra, Indus and their tributaries — are perennial, fed by rain in the monsoon and by snowmelt in summer. The Peninsular rivers — Godavari, Krishna, Kaveri, Mahanadi, Narmada, Tapi — depend on rain and shrink in the dry season. Groundwater in the alluvial plains is the largest usable store; India is the world's largest user of groundwater, pumping about 250 billion cubic metres a year from some two crore wells and tubewells. Rainwater harvested from roofs and fields, and glaciers of the Himalaya, which store water as ice and release it slowly, complete the list.

Uses. Irrigation takes about 80 per cent of all water used; domestic use about 6 per cent; industry about 6 per cent; and hydroelectricity, navigation, fisheries and wildlife the rest. Irrigation comes through canals (Punjab, Haryana, western UP, the Damodar and Mayurakshi commands in West Bengal), wells and tubewells (the largest share today, especially in the Ganga plain), and tanks (the traditional method of Tamil Nadu, Karnataka and Andhra Pradesh).

Multipurpose river valley projects were called the temples of modern India by Jawaharlal Nehru. One dam serves irrigation, hydroelectricity, flood control, water supply, navigation and fisheries. The main projects are Bhakra Nangal on the Sutlej, Hirakud on the Mahanadi (the longest dam in the world, 26 km with dykes), Damodar Valley (Tilaiya, Maithon, Panchet, Konar and the Durgapur barrage), Nagarjuna Sagar on the Krishna, Tungabhadra, Sardar Sarovar on the Narmada, Tehri on the Bhagirathi and Farakka barrage on the Ganga, which feeds the Hooghly to keep Kolkata port alive.

Problems. Uneven distribution: Meghalaya gets 1,100 cm of rain and Jaisalmer 10 cm; the west and south suffer scarcity while the east floods. Seasonal concentration: 75 per cent of rain falls in four months. Over-pumping has lowered the water table by metres in Punjab, Gujarat and even Kolkata. Pollution of rivers by sewage and industry — the Ganga, Yamuna and Damodar are among the worst. Arsenic in the groundwater of Malda, Murshidabad, Nadia and the 24 Parganas poisons drinking water. Conflicts between states over the Kaveri, Krishna and Teesta waters.

Conservation. Rainwater harvesting from rooftops, now compulsory for new buildings in many cities; recharge of groundwater through percolation pits and check dams; watershed management; drip and sprinkler irrigation, which save half the water of flood irrigation; treatment and reuse of waste water; lining canals; growing crops suited to the rainfall; and the proposal to link rivers to move surplus water to deficit basins.

A mineral is a naturally occurring inorganic substance with a definite chemical composition and physical properties, found in the rocks of the crust. Minerals are the raw materials of industry: without iron there is no steel, without coal no thermal power, without limestone no cement. They are non-renewable, localised and unevenly distributed, and their location explains why industries and cities grow where they do.

Classification.

• Metallic minerals yield metals. Ferrous metallic minerals contain iron or are used with it in steel: iron ore, manganese, chromite, nickel, cobalt. Non-ferrous metallic minerals contain other metals: bauxite (aluminium), copper, lead, zinc, tin, gold, silver.
• Non-metallic minerals yield no metal: mica, limestone, gypsum, dolomite, phosphate, graphite, asbestos, salt, and the building stones.
• Mineral fuels or energy minerals: coal, lignite, petroleum, natural gas, uranium and thorium.

Occurrence. Minerals occur as veins and lodes filling cracks in igneous and metamorphic rocks (copper, zinc, tin, gold); as beds and layers in sedimentary rocks, formed by deposition (coal, limestone, gypsum, potash) or by concentration in the sea (iron in banded formations); as residual deposits left when rain leaches away the rest of the rock (bauxite, laterite iron); as placer deposits of heavy grains sorted by rivers and beaches (gold, tin, monazite sands of Kerala); and dissolved in sea water (common salt, magnesium, bromine).

Distribution in India. Because the Peninsular plateau is made of ancient crystalline and metamorphic rocks, almost all of India's metallic minerals lie there, and the coal lies in the Gondwana sedimentary basins of the river valleys that cut it. The great mineral belts are:

• The North-Eastern plateau belt (Chota Nagpur plateau and its extension) — Jharkhand, Odisha, West Bengal and Chhattisgarh — the richest belt, with iron ore, coal, manganese, bauxite, mica, copper and limestone, the base of the Damodar valley industries.
• The South-Western belt — Karnataka and Goa — iron ore, manganese, gold (Kolar, Hutti) and limestone.
• The Central belt — Madhya Pradesh, Chhattisgarh, Maharashtra, Andhra Pradesh — manganese, bauxite, limestone, diamonds at Panna, coal.
• The North-Western belt — Rajasthan and Gujarat — copper, zinc, lead, gypsum, rock phosphate, petroleum and salt.
• The Himalayan belt — small deposits of copper, lead, zinc and cobalt, little exploited.
• The offshore and coastal belt — petroleum and gas at Mumbai High and the Krishna-Godavari basin, monazite and ilmenite sands of Kerala.

The Northern Plains, being deep alluvium, have almost no minerals at all except building materials, which is why the heavy industries are all in the peninsula.

Iron ore is the backbone of industry, because iron and steel are the material of machines, railways, ships, bridges, buildings and tools. India has some of the largest and best iron ore reserves in the world, estimated at over 2,800 crore tonnes, and is among the top five producers.

Types of ore. Magnetite is the best ore, black, magnetic, with up to 70 per cent iron; India's magnetite lies in Karnataka, Andhra Pradesh, Tamil Nadu and Kerala. Haematite is red or reddish-brown, with 60–68 per cent iron, and is the ore mined in the greatest quantity, in Odisha, Jharkhand, Chhattisgarh, Karnataka and Goa. Limonite is yellow-brown, 35–50 per cent iron, and siderite is a carbonate ore with 30–48 per cent; both are of little importance in India.

Distribution. Over 95 per cent of India's reserves lie in Odisha, Jharkhand, Chhattisgarh, Karnataka and Goa. In Odisha the Sundargarh–Keonjhar–Mayurbhanj belt (Barbil, Joda, Gorumahisani, Badampahar) is the largest producer in the country. In Jharkhand the Singhbhum district (Noamundi, Gua, Kiriburu) feeds Jamshedpur and Bokaro. In Chhattisgarh the Bailadila range of Dantewada has fourteen deposits of very high-grade ore, exported through Visakhapatnam to Japan, and the Dalli-Rajhara mines feed Bhilai. In Karnataka the Bellary–Hospet–Sandur belt and Kudremukh in Chikkamagaluru supply Vijayanagar and export through Mangalore. Goa exports its ore through Marmagao. West Bengal has no worked iron ore, but its steel plants at Durgapur and Burnpur draw ore from Jharkhand and Odisha next door.

Uses. Almost all iron ore goes to make pig iron in blast furnaces with coke and limestone, and then steel. India exports ore from Bailadila, Goa and Karnataka to Japan, Korea and China.

Manganese is the mineral that turns iron into good steel. About 10 kg of manganese are needed for every tonne of steel; it removes oxygen and sulphur and makes the steel hard and tough. Manganese is also used in dry-cell batteries, in bleaching powder, in paints, insecticides and glass. The ore is pyrolusite, black, found in the ancient Dharwar rocks of the peninsula.

Distribution of manganese. India holds about 20 per cent of the world's reserves. Odisha is the largest producer (Sundargarh, Keonjhar, Bolangir, Koraput), followed by Maharashtra (Nagpur, Bhandara), Madhya Pradesh (Balaghat, Chhindwara), Karnataka (Shimoga, Bellary, Chitradurga) and Andhra Pradesh (Srikakulam, Vizianagaram). Balaghat has the biggest single mines. Manganese is exported through Visakhapatnam and Marmagao, though most is now used at home in the steel plants.

Coal is India's most important mineral fuel and the source of about half of the country's commercial energy and over 70 per cent of its electricity. It is a sedimentary rock formed from forests buried in swamps millions of years ago, compressed and heated until the carbon content rose. India has reserves of over 30,000 crore tonnes, the fifth largest in the world, and is the second largest producer after China.

Types by carbon content.

• Anthracite — over 90 per cent carbon, hard, burns without smoke, the best coal; found in India only in small quantities in Jammu and Kashmir.
• Bituminous — 60–80 per cent carbon, the most common coal, used for coke, thermal power and industry; almost all Indian coal is bituminous.
• Lignite — 40–60 per cent carbon, brown, soft, high moisture; at Neyveli in Tamil Nadu and in Gujarat and Rajasthan, used in thermal power at the mine mouth.
• Peat — under 40 per cent carbon, the first stage, more like decayed vegetation; found in marshes, of little use.

Two geological ages. About 98 per cent of India's coal is Gondwana coal, about 250 million years old, in the river basins of the peninsula — the Damodar, Sone, Mahanadi, Godavari and Wardha valleys. It is good bituminous coal but has more ash than the world's best. Tertiary coal, about 50 million years old, lies in the north-east (Makum in Assam, Meghalaya, Nagaland), in Jammu and Kashmir and as lignite in Tamil Nadu and Gujarat; it is high in sulphur and less than 2 per cent of production.

Distribution. The Damodar valley of Jharkhand and West Bengal is the heart of Indian coal: Jharia in Jharkhand is the largest and only major source of coking coal; Bokaro, Giridih, Karanpura and Ramgarh are also in Jharkhand; and Raniganj in West Bengal (Paschim Bardhaman) is the oldest coalfield in India, worked since 1774, and the state's largest. Odisha has the vast Talcher and Ib valley fields, now the largest producing state. Chhattisgarh has Korba; Madhya Pradesh Singrauli and Sohagpur; Maharashtra Chandrapur and Wardha valley; Telangana Singareni in the Godavari valley. Almost every field has a thermal power station beside it.

Uses. Thermal electricity (the largest use); coke for blast furnaces in steel making — only Jharia and a few Raniganj seams give coking coal, so India imports coking coal from Australia; fuel for cement, brick, fertiliser and chemical industries; and raw material for coal tar, dyes, benzene and, in the past, town gas. Railways used it until diesel and electricity replaced steam.

Problems. High ash content (25–45 per cent) and low calorific value; concentration in the east, so coal must be hauled 1,500 km to the western and southern plants; underground fires at Jharia burning since 1916; land subsidence; air pollution and carbon dioxide; and the finite life of reserves, perhaps 100 years at current rates.

Petroleum or mineral oil is a liquid mixture of hydrocarbons formed from the remains of marine plants and animals buried in sediments under the sea and slowly changed by heat and pressure over millions of years. It collects in porous rocks such as sandstone and limestone, trapped under a cap of impermeable rock in the top of an anticline or against a fault, usually with natural gas above it and salt water below. Oil is called liquid gold because of its value: it is the fuel of all road, sea and air transport, a source of electricity, and the raw material of the petrochemical industry — plastics, synthetic fibres, fertilisers, detergents, paints, drugs and lubricants.

India's position. India produces about 30 million tonnes a year but consumes over 200 million tonnes, so it imports about 85 per cent of its need, mostly from West Asia, and oil is the largest item in India's import bill. This is why energy security and conservation of oil are national priorities.

Producing regions.

• Assam and the north-east — the oldest oil region. Digboi in Tinsukia district has been producing since 1889 and has India's oldest refinery (1901); Naharkatiya, Moran, Hugrijan and Rudrasagar are the other fields. The Assam oil moves by pipeline to refineries at Guwahati, Bongaigaon, Numaligarh and Barauni in Bihar.
• Gujarat — Ankleshwar on the Narmada was the first big discovery after independence (1958); Kalol, Mehsana, Cambay, Lunej and Kosamba followed, feeding the Koyali refinery near Vadodara.
• Mumbai High — an offshore field in the Arabian Sea, 176 km north-west of Mumbai, discovered in 1974 and drilled from the platform Sagar Samrat; with Bassein and other nearby fields it gives over 60 per cent of India's oil.
• Krishna-Godavari basin on the Andhra coast, the Kaveri basin in Tamil Nadu and Barmer in Rajasthan (Mangala field, 2004, the largest onshore find in decades) are the newer regions.

Refineries turn crude into petrol, diesel, kerosene, LPG, aviation fuel, naphtha and bitumen. India has about 23 refineries; the largest, at Jamnagar in Gujarat, is the largest in the world. West Bengal's refinery is at Haldia, fed by imported crude through the port. Others are at Mathura, Panipat, Koyali, Mumbai, Visakhapatnam, Chennai, Kochi, Barauni and the Assam group.

Natural gas is found with oil (associated gas) or alone (free gas), and consists mainly of methane. It is the cleanest fossil fuel, giving little smoke and less carbon dioxide than coal. It is used for electricity, for fertiliser (as a source of hydrogen for ammonia), for petrochemicals, as CNG in vehicles and as piped gas in kitchens. The largest sources are the Krishna-Godavari basin, Mumbai High and Bassein, the Cambay basin, Assam and Tripura. The HVJ pipeline (Hazira–Vijaipur–Jagdishpur), 1,700 km long, carries gas from the west coast to the fertiliser and power plants of the northern plains, and gas is now also imported as LNG through Dahej and Hazira.

Bauxite is the ore of aluminium, the light, strong, rust-free metal of aircraft, vehicles, electric cables, utensils, foil and building frames. Bauxite is a residual deposit, formed where heavy tropical rain leaches silica and other elements out of aluminium-rich rocks and leaves a red-brown crust of aluminium hydroxides, usually capping laterite plateaus. India has the fifth largest reserves in the world, about 300 crore tonnes. Odisha holds over half — the Panchpatmali deposits of Koraput and the Kalahandi–Bolangir plateaus, worked by NALCO with its smelter at Angul. Gujarat (Jamnagar, Kutch), Jharkhand (Lohardaga, Ranchi), Maharashtra (Kolhapur, Ratnagiri), Chhattisgarh (Amarkantak, Bastar) and Madhya Pradesh (Katni, Jabalpur) are the other producers. Aluminium smelting needs huge amounts of electricity, so smelters stand near power: Hirakud, Renukoot (near Rihand), Korba, Alupuram and Belgaum.

Mica is a non-metallic mineral that splits into thin transparent sheets, does not conduct electricity and withstands heat up to 800 °C. This makes it essential for insulators in electrical and electronic equipment, in radio and television sets, condensers, lamps and as a filler in paints. Mica occurs in veins in the pegmatite rocks of the old crystalline shield. India was once the world's largest producer and is still the largest exporter of sheet mica. The Koderma–Giridih–Hazaribagh belt of Jharkhand is the oldest and most famous mica belt in the world; the Nellore belt of Andhra Pradesh and the Ajmer–Bhilwara–Jaipur belt of Rajasthan are the other two. Synthetic substitutes have reduced demand.

Copper is the metal of electrical wires and cables because it conducts electricity better than any common metal; it is also alloyed with zinc to make brass and with tin to make bronze, and used in coins, utensils and electronics. India's copper deposits are small and low grade, so most copper is imported. The producers are the Khetri belt of Jhunjhunu district in Rajasthan, the Singhbhum belt of Jharkhand (Mosabani, Ghatsila, where Hindustan Copper's smelter stands) and the Malanjkhand mine of Balaghat in Madhya Pradesh, the largest single deposit.

Limestone is a sedimentary rock of calcium carbonate laid down in ancient seas. It is the raw material of cement, which takes about three-quarters of production, and a flux in blast furnaces, where it combines with the impurities of the iron ore to form slag; it is also used in the chemical industry for lime, bleaching powder and soda, in glass, paper, sugar refining and as a building stone. Limestone is widely spread: Madhya Pradesh (Satna, Katni, Jabalpur), Rajasthan (Jodhpur, Chittorgarh), Andhra Pradesh, Chhattisgarh, Gujarat, Karnataka and Tamil Nadu are the main producers; in West Bengal small deposits occur in Purulia, Bankura and the Darjeeling foothills, and the Durgapur cement plant draws on Sundargarh in Odisha.

Other minerals. Gold at Kolar and Hutti in Karnataka; diamonds at Panna in Madhya Pradesh; zinc and lead at Zawar in Rajasthan; chromite in Sukinda, Odisha (98 per cent of India's); gypsum in Rajasthan for cement and fertiliser; dolomite in Odisha and Chhattisgarh for steel; rock phosphate at Jhamarkotra, Udaipur, for fertiliser; and salt from the sea at Gujarat and Tamil Nadu and from the Sambhar lake.

Power resources are the resources from which energy is obtained to run machines, light homes and move vehicles. They are divided into conventional sources, which have been used for a long time, are mostly non-renewable and pollute — coal, petroleum, natural gas, firewood, and also hydroelectricity and nuclear power; and non-conventional sources, newly developed, renewable and clean — solar, wind, tidal, wave, geothermal and biomass energy. India's electricity comes about 70 per cent from thermal (coal, gas, oil), about 12 per cent from hydro, about 3 per cent from nuclear and a fast-growing share, now over 15 per cent, from wind and solar.

Thermal power is generated by burning coal, gas or oil to make steam that turns a turbine. Coal-based stations are built at the coalfields (pit-head stations) or at ports and load centres. The largest are Vindhyachal, Mundra, Talcher, Korba, Singrauli, Ramagundam, Rihand and Sipat. In West Bengal the main stations are Kolaghat, Bakreswar, Sagardighi, Bandel, Santaldih, Mejia (DVC) and Farakka (NTPC), all burning Raniganj and Jharkhand coal, and Haldia and Budge Budge near Kolkata. Thermal power is reliable and can be built anywhere fuel can reach, but it uses a non-renewable fuel, emits carbon dioxide, sulphur and fly ash and consumes large amounts of cooling water.

Hydroelectricity is generated when water falling from a height turns a turbine. It needs a steady flow of water, a fall or a dam to create one, and a reservoir. Once built it is cheap, clean, renewable and quick to start, and the dam also gives irrigation and flood control. India's potential is about 1.5 lakh MW, of which less than a third is developed. The main plants are Bhakra Nangal (Sutlej), Tehri (Bhagirathi), Nathpa Jhakri (Sutlej), Sardar Sarovar (Narmada), Koyna (Maharashtra), Sharavathi and Jog (Karnataka), Idukki (Kerala), Srisailam and Nagarjuna Sagar (Krishna), Hirakud (Mahanadi) and Salal and Baglihar (Chenab). In West Bengal hydro plants are small and in the hills: Jaldhaka, Rammam and the Teesta canal stations in Darjeeling and Jalpaiguri, and the Purulia pumped storage plant in the Ayodhya hills, which pumps water up at night and generates by day. The disadvantages are the drowning of forests and villages by reservoirs, the displacement of people (the Narmada dispute), silting, earthquake risk and dependence on rainfall.

Nuclear power comes from the heat released when atoms of uranium-235 or plutonium split in a controlled chain reaction; the heat makes steam as in a thermal plant. A tiny amount of fuel gives enormous energy — one kilogram of uranium equals about 3,000 tonnes of coal — and there is no smoke or carbon dioxide. India's uranium comes from Jaduguda in Singhbhum, Jharkhand, and newer mines in Andhra Pradesh; its very large thorium reserves in the monazite sands of Kerala are the basis of the long-term programme. The power stations are at Tarapur (Maharashtra, the first, 1969), Rawatbhata (Rajasthan), Kalpakkam (Tamil Nadu), Narora (Uttar Pradesh), Kakrapar (Gujarat), Kaiga (Karnataka) and Kudankulam (Tamil Nadu, the largest). The dangers are radiation leaks, the disposal of waste that stays radioactive for thousands of years, very high cost and the risk of accidents like Chernobyl and Fukushima.

Non-conventional or renewable sources of energy are those that are replenished by nature continuously and can never be exhausted — sunlight, wind, tides, waves, the heat of the earth and the energy of plant and animal waste. They were little used before the 1970s; the oil crisis of 1973, the pollution of coal and the fear of climate change have made them the fastest growing part of India's energy supply. India set up a separate Ministry of New and Renewable Energy and now has over 1.7 lakh MW of renewable capacity, the fourth largest in the world.

Solar energy. India receives sunshine on about 300 days a year, so its potential is enormous. Photovoltaic cells turn sunlight directly into electricity; solar thermal collectors heat water or, with mirrors, raise steam. Solar power lights villages far from the grid, pumps irrigation water, cooks food in solar cookers and heats bathwater on rooftops. Huge solar parks stand at Bhadla in Jodhpur (over 2,000 MW), Pavagada in Karnataka, Kurnool in Andhra Pradesh, Charanka in Gujarat and Rewa in Madhya Pradesh. The drawbacks are night and cloud, the land needed and the cost of storage batteries. India led the founding of the International Solar Alliance in 2015.

Wind energy. Wind turbines turn the movement of air into electricity. India has the fourth largest wind capacity in the world, over 40,000 MW. The best sites are the coasts and the gaps in the hills through which the monsoon blows: Tamil Nadu (Muppandal near Kanyakumari, the largest wind farm in India, and the Palghat gap), Gujarat (Kutch, Jamnagar), Maharashtra (Satara), Karnataka, Rajasthan (Jaisalmer) and Andhra Pradesh. In West Bengal there are small wind farms at Frazerganj in the Sundarbans coast. Wind is clean and cheap once installed, but it is not steady, needs open windy land and the turbines are noisy.

Tidal and wave energy. The rise and fall of the tide can drive turbines in a barrage across a bay. The Gulf of Kutch and the Gulf of Khambhat in Gujarat, with tides of 8–11 m, and the Sundarbans creeks are the sites identified; a small plant was tried at Durgaduani creek in the Sundarbans. Wave energy has been tested at Vizhinjam in Kerala. Both are still experimental.

Geothermal energy uses the heat of hot springs and rocks below the surface. Manikaran in the Parvati valley of Himachal Pradesh and Puga valley in Ladakh have pilot plants; the Bakreswar hot springs of Birbhum, West Bengal, are a possible site.

Biomass and biogas. Cow dung, crop waste and kitchen waste fermented in a gobar gas plant give methane for cooking and lighting and a rich manure; millions of such plants work in Indian villages. Crop residues burnt in power plants, ethanol from sugarcane molasses mixed into petrol, and biodiesel from jatropha are other forms. Firewood, still the fuel of half the villages, is biomass too, but its over-use destroys forests.

Non-conventional sources are clean, renewable and often local, so they can bring power to remote villages without transmission lines. Their weaknesses are that they depend on weather, need storage and large areas of land, and are still costlier in some cases. The future of India's energy lies in combining them with conventional sources.

Conservation means the wise, planned and careful use of resources so that they are not wasted, not destroyed and remain available for future generations. It does not mean not using resources; it means using them in a way that gets the greatest benefit for the longest time. The idea is summed up in the word sustainable development: development that meets the needs of the present without compromising the ability of future generations to meet their own needs, as the Brundtland Report of 1987 defined it.

Why conservation is necessary.

• Non-renewable resources are finite. At present rates the world's known petroleum may last about 50 years, natural gas 50–60 years and coal 100–150 years. Iron, copper and bauxite are also limited; high-grade ores are being exhausted first.
• Renewable resources can be destroyed by over-use. Forests cut faster than they grow, fish caught faster than they breed, groundwater pumped faster than rain recharges it and soil eroded faster than it forms all turn into non-renewable losses.
• Population and demand are growing. India's population has grown four times since independence and consumption per person is also rising.
• Resource use pollutes. Burning fossil fuels causes air pollution, acid rain and global warming; mining scars the land and poisons rivers; over-irrigation causes salinity.
• Justice. Resources belong to future generations as much as to us, and to the poor as much as to the rich.

Methods of conservation.

• The three Rs — Reduce, Reuse, Recycle. Reduce consumption by switching off lights, walking short distances, avoiding plastic; reuse containers, paper and water; recycle metals, glass, paper and plastics. Recycling aluminium uses only 5 per cent of the energy of smelting new metal.
• Efficient technology — LED lamps, fuel-efficient engines, energy-rated appliances, drip irrigation, supercritical boilers that burn less coal per unit.
• Substitution — replacing scarce resources by abundant ones: solar and wind for coal, aluminium and optical fibre for copper, bamboo and recycled fibre for wood pulp, CNG for petrol.
• Scientific management of renewable resources — cutting forests on a rotation with replanting, closed seasons for fishing, watershed management for water, crop rotation and contour bunding for soil.
• Reducing waste in extraction — better mining recovery, use of low-grade ores and of fly ash for bricks and cement.
• Laws and planning — the Forest Conservation Act, the Environment Protection Act, the Energy Conservation Act 2001 and the Bureau of Energy Efficiency, environmental clearance for projects, and international agreements such as the Paris climate agreement.
• Public awareness — education, Earth Hour, Vana Mahotsava, and movements such as Chipko and the Narmada Bachao Andolan.

The role of the individual. Conservation at the national scale is the sum of millions of small choices: a student who closes a running tap, uses both sides of a page, takes public transport, separates waste for recycling and plants a tree is practising resource conservation. Gandhi said that the earth provides enough for everyone's need but not for anyone's greed; that sentence is the whole philosophy of the subject.