Environmental pollution: meaning, classification and the legal frame

Detail

1. What environmental pollution means

• Environmental pollution is the release of substances and energy from the waste products of human activities.
• It harms living things (people, animals, plants) and property (buildings, crops, monuments).

• "Energy" counts too. Noise and heat can pollute even when no material substance is released.

• Classification by medium: pollution is grouped by the medium (the carrier: the air, water or soil that holds the pollutant and spreads it) through which pollutants travel and diffuse (spread outwards from the source).

• This gives four types: air, water, land and noise.

• Pollution vs pollutants (a classic NCERT exercise question):

Term	What it is	Example
Pollution	The harmful condition or state of the environment	The Yamuna made unfit for bathing
Pollutant	The substance or energy that causes that condition	Untreated sewage, coliforms, industrial chemicals

• Why it matters: One pollutant can move from one medium to another.
• Sulphur oxides from a chimney → mix with rain as acid rain → fall into lakes and soil.
• Pesticides sprayed on fields → washed off in farm run-off (rainwater flowing over farmland) → reach rivers and groundwater.

2. The four types: pollutants and their sources (NCERT Table 9.1)

Type	Main pollutants	Main sources
Air	Oxides of sulphur (SO₂) and nitrogen (NOₓ), carbon monoxide (CO), hydrocarbons, ammonia, lead, aldehydes, asbestos, beryllium	Combustion (burning) of coal, petrol and diesel; industrial processes; disposal of solid waste and sewage
Water	Odour, dissolved and suspended solids, ammonia and urea, nitrates and nitrites, chlorides, fluoride, carbonates, oil and grease, pesticide residue, coliforms, sulphate and sulphide, heavy metals (e.g. lead, arsenic, mercury, manganese), radioactive substances	Sewage; urban run-off; agricultural run-off; industries; nuclear power plants
Land	Human and animal excreta, viruses and bacteria, garbage and vectors (carriers of disease such as flies), pesticide and fertiliser residues, alkalinity, fluorides, radioactive substances	Improper habits of humans; disposal of untreated industrial waste; overuse of pesticides and fertilisers
Noise	Very high levels of sound	Aircraft, motor vehicles, trains, industrial processes, advertising media (loudspeakers)

• Key terms explained:
• Coliforms: bacteria found in human and animal excreta. If they are in water, it means sewage is present. They are the standard test for whether water is safe to drink or bathe in.
• Heavy metals: dense metals like lead, mercury, cadmium and arsenic. They do not break down. They build up in the body and in food chains.
• Hydrocarbons: compounds of hydrogen and carbon given off by unburnt fuel. In sunlight they help form smog.
• Run-off: rainwater that flows over the ground into drains and rivers, carrying dirt, chemicals and waste with it.

3. The legal frame in India

3.1 Timeline of the core laws

Year	Law or body	What it does
1974	Water (Prevention and Control of Pollution) Act	India's first full law on water pollution. It bans discharging pollutants into water bodies above set standards and lays down penalties for breaking the rules [7][12]. It created the CPCB and the SPCBs.
1981	Air (Prevention and Control of Pollution) Act	It can ban polluting fuels and substances. Anyone setting up or running an industrial plant in a declared air pollution control area needs consent from the state board [12].
1986	Environment (Protection) Act (EPA)	An umbrella law passed after the Bhopal gas tragedy (1984).
2010	National Green Tribunal (NGT) Act	Sets up a special court for environmental cases [8].

3.2 Central Pollution Control Board (CPCB)

• CPCB is the national statutory body (a body created by an Act of Parliament) for preventing and controlling pollution. It was set up in 1974 under the Water Act.
• Its powers were later extended to air pollution under the Air Act 1981.

• State Pollution Control Boards (SPCBs) do the same work in each state. In Union Territories this is done by Pollution Control Committees (PCCs).

• Water quality network:

• Monitoring began in 1976 with just 18 stations on the Yamuna [2].
• The National Water Quality Monitoring Programme (NWMP) now covers 4,736 locations, including 2,155 locations on 645 rivers [2]. (NCERT: 507 stations.)

• A 2022 count gave 2,108 locations on 719 rivers across 28 states and 7 UTs [3].

• Air quality network:

• The National Ambient Air Quality Monitoring Programme (NAMP) is run under the Air Act 1981 by the CPCB with the SPCBs, the PCCs and NEERI (National Environmental Engineering Research Institute, Nagpur) [4].
• Ambient air means the open outdoor air that people breathe.

• In 2024 the network had 1,447 stations (516 continuous real-time + 931 manual) covering 516 cities in 28 states and 7 UTs [4].

• Critically polluted river stretches (CPRS):

• CPCB ranks river stretches by BOD (Biochemical Oxygen Demand: the amount of oxygen that bacteria use up to break down organic waste in water; a higher BOD means dirtier water).
• The number of CPRS fell from 45 (2018) to 37 (2025) [5][6].
• 149 stretches were delisted (removed from the list), and 71 showed better water quality compared with the 2018 report [5][6].
• Seven stretches have BOD above 30 mg/l: 4 in Gujarat, 2 in Maharashtra, 1 in Assam [5][6].

3.3 Environment (Protection) Act 1986: the umbrella law

• Why it came:
• Bhopal gas tragedy (December 1984): methyl isocyanate gas leaked from the Union Carbide pesticide plant in Bhopal (Madhya Pradesh).
• This showed that the Water Act and the Air Act did not cover hazardous substances (dangerous chemicals) or the environment as a whole.

• Result: Parliament passed one umbrella law in 1986.

• What "umbrella" means:

• It gives a framework to coordinate the central and state authorities set up under the Water Act 1974 and the Air Act 1981 [7].

• The Centre gets broad powers that fill the gaps the older laws left.

• Powers of the Centre:

• It sets emission standards (limits on what can go into the air) and discharge standards (limits on what can go into water) for industries.
• It controls the handling of hazardous substances.

• It can issue directions under Section 5, including closing a polluting unit or cutting its power and water supply. Appeals against these directions go to the NGT [7][8].

• Recent change, Jan Vishwas (Amendment of Provisions) Bill 2022:

• It amends 42 laws, including the EPA [9].
• Under the Air Act and the EPA, Adjudicating Officers now decide penalties. Appeals against their orders go to the NGT [9].
• This shifts minor violations from criminal prosecution towards monetary penalties.

3.4 National Green Tribunal (2010)

• The NGT is a special court for environmental cases, set up under the NGT Act 2010 [8].
• It hears cases under the main green laws, including the Water, Air and Environment (Protection) Acts. It also hears appeals against orders made under them [8][9].

3.5 Policy layer on top of the laws

• National Clean Air Programme (NCAP, 2019):
• It covers 131 cities, most of them non-attainment cities (cities that keep failing the national air quality standards) [10].
• Target: up to 40% cut in PM10 by 2025-26 [11].

• PM10 means particles 10 micrometres across or smaller. They are small enough to enter the lungs.

• Namami Gange (2014) works on water pollution in the Ganga basin. Swachh Bharat Mission (2014) works on land pollution from excreta and garbage.

4. The recurring problem: weak enforcement

• Laws exist, but follow-up is weak.
• SPCBs are short of staff, laboratories and money.
• Penalties are low compared with what it costs an industry to treat its waste.

• Many sources are scattered (non-point sources: farm run-off, open burning, household sewage). They are hard to licence and monitor, unlike a single factory pipe (point source).

• Result: pollution continues even where standards are clear. Courts and the NGT often step in where regular regulation has failed.

Prelims Hooks

• Pollution is classified by medium: air, water, land and noise (NCERT Table 9.1).
• Pollution = the harmful condition. Pollutant = the substance or energy that causes it.
• Asbestos, beryllium, aldehydes and lead are listed as air pollutants. Coliforms are listed as water pollutants.
• Advertising media is listed as a source of noise pollution.
• Chronological order: Water Act (1974) → Air Act (1981) → Bhopal gas tragedy (1984) → Environment (Protection) Act (1986) → NGT Act (2010).
• CPCB was created under the Water Act 1974, not the Air Act. A common trap.
• NAMP runs under the Air Act 1981, with SPCBs, PCCs and NEERI [4].
• CPCB water monitoring began in 1976 with 18 stations on the Yamuna [2].
• Critically polluted river stretches: 45 (2018) → 37 (2025). Stretches with BOD above 30 mg/l are in Gujarat (4), Maharashtra (2) and Assam (1) [5][6].
• NCAP (2019): 131 cities, target of up to 40% PM10 cut by 2025-26 [10][11].

Mains Points

• Pollution as a geographical problem:
• Pollutants move through media: air → rain → soil and water.

• So the damage spreads far beyond the source. Examples: industrial belts, the Indo-Gangetic plain's winter smog, and polluted stretches in Gujarat and Maharashtra [5].

• Evolution of the legal frame:

• The early laws covered one medium each (water 1974, air 1981).
• The Bhopal disaster (1984) showed their gaps and led to the umbrella EPA 1986.
• Specialised justice came through the NGT (2010).

• Penalties are now being decriminalised under Jan Vishwas [7][9].

• Data-driven governance:

• The monitoring network grew from 18 stations (1976) to 4,736 water locations and about 1,450 air stations [2][4].

• This makes targeted plans possible, such as delisting river stretches and city-wise PM10 targets under NCAP [5][11].

• The gap is enforcement:

• Weak SPCBs, low penalties and scattered non-point sources keep pollution high.
• Ways forward: stronger SPCBs, real-time public data, the "polluter pays" principle, and treatment of urban sewage and solid waste (Namami Gange, Swachh Bharat).