Environment and pollution: meaning, components, kinds and effects

1. Meaning of environment

The word comes from the French environner, to surround. In ecology, environment is the sum of the physical, chemical and biological conditions that surround a living organism and influence its life. It is a system, not a list: each component acts on the others.

The legal definition is in section 2(a) of the Environment (Protection) Act, 1986: “environment” includes water, air and land and the inter-relationship which exists among and between water, air and land, and human beings, other living creatures, plants, micro-organism and property. Three points are worth making in an answer.

• The definition is inclusive (“includes”), so courts may extend it.
• It protects the inter-relationship, not only the media. Harm to a river that destroys fisheries and the livelihood of fishermen is harm to the environment.
• It includes property, so damage to buildings and monuments by pollution (the Taj Mahal, for example) falls within it.

2. Components of environment

• Abiotic (non-living): the atmosphere (air), the hydrosphere (water in seas, rivers, lakes and underground) and the lithosphere (soil and rock), together with energy from the sun.
• Biotic (living): producers (green plants), consumers (animals, including humans) and decomposers (bacteria, fungi). Together with the abiotic components they make the biosphere.
• The built or cultural environment: towns, monuments, heritage, which the law also protects.

An ecosystem is a unit in which these components interact, such as a forest, a lake or a wetland. Ecosystems supply what are called ecosystem services: provisioning services (food, water, timber, medicine), regulating services (climate regulation, flood control, purification of water and air, pollination), cultural services (recreation, spiritual and religious value) and supporting services (soil formation, nutrient cycling). The idea explains why the law values a wetland or a forest beyond its timber or land price.

3. Meaning of pollution

In general terms, pollution is the introduction by man of substances or energy into the environment that causes harm to living resources, hazards to human health, damage to property or interference with legitimate uses of the environment. Each statute defines it for its own medium.

• Water: section 2(e) of the Water (Prevention and Control of Pollution) Act, 1974 defines “pollution” as such contamination of water, or alteration of its physical, chemical or biological properties, or discharge of sewage, trade effluent or any other substance into water, as may or is likely to create a nuisance or render the water harmful or injurious to public health or safety, to domestic, commercial, industrial, agricultural or other legitimate uses, or to the life and health of animals, plants or aquatic organisms.
• Air: section 2(a) of the Air (Prevention and Control of Pollution) Act, 1981 defines “air pollutant” as any solid, liquid or gaseous substance (including noise) present in the atmosphere in such concentration as may be or tend to be injurious to human beings, other living creatures, plants, property or environment; section 2(b) makes “air pollution” the presence of any air pollutant in the atmosphere. Noise was added in 1987.
• Environment generally: sections 2(b) and 2(c) of the 1986 Act define an “environmental pollutant” as any solid, liquid or gaseous substance present in such concentration as may be or tend to be injurious to environment, and “environmental pollution” as its presence in the environment.

4. Sources and kinds of pollution

Sources are classed as natural (volcanoes, forest fires, dust storms, floods) and man-made (anthropogenic). A second classification is point sources (a factory outlet, a sewage pipe) and non-point sources (run-off of fertilisers and pesticides from farmland, vehicle exhaust spread over a city). Point sources are easier to regulate, which is why the consent system under the Water and Air Acts targets outlets and plants.

• Air pollution: particulate matter, sulphur dioxide, oxides of nitrogen, carbon monoxide, ozone, lead; from industry, thermal power, vehicles, crop-residue burning, construction dust. Effects: respiratory and heart disease, acid rain, damage to buildings (the “marble cancer” of the Taj).
• Water pollution: sewage, industrial effluents, agricultural run-off, oil spills, thermal discharge. Effects: water-borne disease, eutrophication, death of aquatic life, contamination of groundwater (the Bichhri case).
• Land and soil pollution: solid waste, hazardous waste, plastics, mining overburden, excessive chemical inputs.
• Noise pollution: traffic, industry, loudspeakers, firecrackers, construction. Effects: hearing loss, stress, sleep disturbance, high blood pressure.
• Radioactive pollution: nuclear accidents and radioactive waste (Chernobyl, 1986; Fukushima, 2011).
• Thermal and light pollution, and marine pollution.

5. Man-made causes of environmental degradation

• Population growth and urbanisation: pressure on land, water and housing; slums without sanitation (the facts of Ratlam).
• Industrialisation without pollution control, and hazardous industries near habitation (Bhopal, 1984; the oleum leak, 1985).
• Deforestation for agriculture, mining, dams, roads and townships.
• Mining and quarrying (the Doon valley limestone quarries).
• Intensive agriculture: chemical fertilisers, pesticides, over-drawing of groundwater, stubble burning.
• Transport: vehicle emissions, which led the Supreme Court in the Delhi cases to order public transport to shift to CNG.
• Consumerism and waste: plastics, electronic waste, unsegregated municipal waste.
• Poverty. At Stockholm in 1972 Indira Gandhi asked whether poverty and need are not the greatest polluters: the poor have no choice but to draw on forests and commons to survive.

6. Global warming and climate change

The earth's surface is kept warm by the greenhouse effect: gases in the atmosphere let sunlight in but trap part of the heat radiated back from the earth. The main greenhouse gases are carbon dioxide, methane, nitrous oxide and fluorinated gases. Burning of fossil fuels, deforestation and some agricultural practices have raised their concentration since the industrial revolution, and the average surface temperature has risen. That rise is global warming; the wider change in weather patterns it produces is climate change.

Effects: melting of glaciers and polar ice, rise in sea level threatening coastal areas and island States, more frequent and severe heat waves, droughts, floods and cyclones, loss of biodiversity, coral bleaching, falling crop yields, spread of vector-borne disease, and displacement of people. India is especially exposed through the monsoon, the Himalayan glaciers and a long, densely populated coastline.

The legal response is international (the UNFCCC, 1992, the Kyoto Protocol, 1997 and the Paris Agreement, 2015) and, since 2024, constitutional: in M.K. Ranjitsinh v. Union of India, 2024 INSC 280, the Supreme Court recognised a right against the adverse effects of climate change as part of Articles 14 and 21. The treaties and that case are covered in the Unit III and Unit II notes.

How this is examined

June 2025 asked “Define the term pollution and explain the different kinds of pollution”, with an alternative on global warming, and a short note on ecosystem services. February 2025 asked for a note on “environment” and an essay on the kinds of pollution “listed under various laws in India”, which is a direct call for the definitions in section 2 of each Act. January 2026 set a short note on man-made causes of pollution and degradation.

For the 10-mark question: general meaning, the three statutory definitions, sources (natural and man-made, point and non-point), then each kind with its causes and effects, and close with the Act that controls it (Water Act, Air Act, Noise Rules 2000, EPA rules on waste). For global warming, give the mechanism, the effects and one paragraph on Kyoto, Paris and Ranjitsinh.