Water Quality, Conservation & NCERT Exercises

NCERT India: People and Economy — Unit III, Chapter 4 (Part 3)

From Quantity to Quality: India's Other Water Crisis

So far we have looked at how much water India has and where it goes. But there is a second crisis quietly running alongside the quantity crisis: the quality of the water that remains. Available water resources are degrading rapidly. India's rivers carry chemical and biological pollution, her groundwater is contaminated with arsenic, fluoride and nitrates in places, and her urban tanks have shrunk under the weight of construction. This part of the chapter examines water-quality issues, the conservation and management measures that can rescue the situation, and closes with a complete walk-through of the NCERT end-of-chapter exercises.

4.3 Deterioration of Water Quality

The per-capita availability of water is dwindling because of population growth. At the same time, the available resources are being polluted with industrial, agricultural and domestic effluents, further limiting usable supplies. When toxic substances enter lakes, streams, rivers and oceans, they get dissolved or lie suspended in water. The result is pollution — water quality deteriorates and aquatic ecosystems are damaged. Sometimes these pollutants seep down and pollute the groundwater as well.

Sources of Water Pollution

The major rivers of the country generally retain better water quality in the less densely populated upper stretches in hilly areas. In the plains, river water is used intensively for irrigation, drinking, domestic and industrial purposes. Drains carrying agricultural fertilisers and insecticides, domestic solid and liquid wastes, and industrial effluents all join the rivers. The concentration of pollutants is especially high during the summer season when river flow is low.

India's Most Polluted Rivers

The Central Pollution Control Board (CPCB), in collaboration with State Pollution Control Boards, monitors water quality at 507 stations across India. The data show that organic and bacterial contamination continues to be the main pollution problem. The Yamuna is the most polluted river in the country between Delhi and Etawah. Other severely polluted stretches include the Sabarmati at Ahmedabad, the Gomti at Lucknow, the Kali, the Adyar, the Cooum (entire stretches), the Vaigai at Madurai, the Musi of Hyderabad and the Ganga at Kanpur and Varanasi.

Groundwater Pollution

Groundwater pollution has occurred due to high concentrations of heavy metals, fluoride and nitrates in different parts of the country. In particular:

• Arsenic — affects parts of West Bengal and Bihar, where over-extraction has drawn arsenic-bearing layers into the active aquifer.
• Fluoride — affects parts of Rajasthan and Maharashtra, where deep aquifers naturally carry fluoride; over-pumping concentrates it further.
• Nitrates — from fertilisers, especially in heavily-irrigated agricultural belts.

Legislative Response

India has put in place a series of laws to control water pollution — most notably the Water (Prevention and Control of Pollution) Act, 1974, the Water Cess Act, 1977, and the Environment Protection Act, 1986. However, implementation has been weak. As of 1997, 251 polluting industries were located along rivers and lakes; the Cess Act has had only marginal impact. There is a strong need to generate public awareness about the importance of water and the impact of pollution. Public action can be very effective in reducing pollutants from agricultural, domestic and industrial sources.

Water Conservation and Management

Given the declining availability of freshwater and the rising demand, the need has arisen to conserve and effectively manage this precious life-giving resource for sustainable development. Sea/ocean water is largely ineffective for human use because of the high cost of desalination. India therefore has to take quick steps and make effective policies and laws, and adopt practical measures for conservation. Besides developing water-saving technologies and methods, attempts must also be made to prevent pollution. There is an urgent need to encourage watershed development, rainwater harvesting, water recycling and reuse, and conjunctive use of water for sustaining supply over the long run.

Recycling and Reuse of Water

One way to expand fresh-water availability is by recycling and reusing. Reclaimed wastewater of lesser quality can be used by industries for cooling and fire-fighting — reducing water cost. In urban areas, water from bathing or washing utensils can be used for gardening. Water used to wash vehicles can also be redirected to gardening. This conserves better-quality water for drinking. Currently, recycling is practised on a limited scale, but there is enormous scope for replenishing supplies through it.

Watershed Management

Watershed management^? refers to the efficient management and conservation of surface and groundwater resources within a defined drainage basin. It involves the prevention of runoff and the storage and recharge of groundwater through methods like percolation tanks, recharge wells, contour bunds, check-dams and afforestation. In a broader sense, watershed management includes the conservation, regeneration and judicious use of all natural resources — land, water, plants and animals — together with people. It seeks to bring about balance between natural resources and society, and its success depends critically on community participation.

The Central and State Governments have launched many watershed development programmes, some of which are also being implemented by NGOs. Haryali is a centrally-sponsored watershed development project that aims at enabling rural populations to conserve water for drinking, irrigation, fisheries and afforestation, executed through Gram Panchayats with people's participation. Neeru-Meeru ("Water and You") in Andhra Pradesh and the Arvari Pani Sansad in Alwar, Rajasthan, have built percolation tanks, dug-out ponds (johads) and check-dams through community effort. Tamil Nadu has made rainwater-harvesting structures compulsory in all new buildings.

Case Study: Ralegan Siddhi, Maharashtra

Other model watershed cases include Hiware Bazar in Maharashtra (close to Ralegan Siddhi) and Sukhomajri in Haryana — pioneer of the participatory watershed approach in the 1970s. In these villages, integrated treatment of land and water has revived agriculture and reversed migration.

Rainwater Harvesting

Rainwater harvesting^? is a method of capturing and storing rainwater for various uses. It is also used to recharge groundwater aquifers. It is a low-cost and eco-friendly technique that preserves every drop of water by guiding rain into borewells, pits and wells. Rainwater harvesting increases water availability, checks the declining groundwater table, improves the quality of groundwater through dilution of contaminants like fluoride and nitrates, prevents soil erosion and flooding, and arrests salt-water intrusion in coastal areas if used to recharge aquifers.

Traditional Rainwater Harvesting in India

Indians have practised rainwater harvesting for centuries through diverse local techniques. In rural areas it is done using surface storage bodies like lakes, ponds and irrigation tanks. Some celebrated traditional structures:

Modern Rooftop Rainwater Harvesting

There is wide scope to use rainwater-harvesting technique to conserve precious water. It can be done by harvesting rainwater on rooftops and open spaces. Harvesting rainwater also decreases the community's dependence on groundwater for domestic use. Besides bridging the demand-supply gap, it can save the energy used to pump groundwater, since recharge raises the water-table. Rainwater harvesting is being taken up on a massive scale in many states. Urban areas can specially benefit, as water demand has already outstripped supply in most cities and towns. Apart from these, the issues of desalination of brackish water in arid and semi-arid areas, inter-linking of rivers from surplus to deficit basins, and the pricing of water are also important — though contested — remedies for India's water problem.

National Water Policy and Schemes

Successive governments have framed National Water Policies in 1987, 2002 and 2012 to provide a national framework for assessing the situation and making recommendations for conservation, development and management of water resources.

Highlights of National Water Policy 2012

National Water Mission

The National Water Mission, announced under the National Action Plan on Climate Change, aims to ensure integrated water-resource development with greater equity, distribution, conservation and efficient use — with a target of improving water-use efficiency by 20 per cent.

Atal Bhujal Yojana (Atal Jal), 2019

Atal Bhujal Yojana — launched in 2019 — is being implemented in 8,220 water-stressed Gram Panchayats across 229 administrative blocks/talukas in 80 districts of seven states: Gujarat, Haryana, Karnataka, Madhya Pradesh, Maharashtra, Rajasthan and Uttar Pradesh. These states account for about 37 per cent of all over-exploited, critical and semi-critical groundwater blocks in India. The key idea is to bring about a behavioural change in the community — from consumption to conservation and smart water management.

Jal Kranti Abhiyan (2015–16)

The Jal Kranti Abhiyan, launched in 2015–16, aims to ensure water security through per-capita availability. Its components include: identifying one water-stressed village in each of 672 districts as a "Jal Gram"; developing model command areas of about 1,000 hectares in each region; abatement of pollution; construction of arsenic-free wells in selected areas; and creating mass awareness through schools, social media and the press.

Conclusion: From Crisis to Conservation

Water has moved, in a single generation, from being seen as an inexhaustible gift of the monsoon to being recognised as a scarce resource that must be assessed, conserved and shared with care. India sits on only 4 per cent of the world's water but supports more than 17 per cent of its people; her per-capita availability has slipped from 5,177 m³ to roughly 1,341 m³; her rivers carry growing pollution and her groundwater is being depleted in heartland states. The way forward lies less in giant dams and more in watershed-led, community-driven, decentralised conservation — combined with cleaner industries, better-priced water and a culture of reuse. Ralegan Siddhi shows what is possible at one end of the spectrum, and the National Water Policy lays down the principles at the other. The choices made in the next two decades will determine whether India keeps her water within the stress zone or slips into permanent scarcity.

NCERT Exercises — with Model Answers