Pollution Control & Waste Management

Syllabus Unit: Environment & Ecology

Why it matters

Chapter overview

India's pollution-control framework rests on two 20th-century laws — the Water Act (1974) and Air Act (1981) — that created the CPCB, and has been steadily extended by 21st-century rules covering solid waste, e-waste and single-use plastics, alongside two flagship missions, Swachh Bharat and Namami Gange, aimed at cleaning up sanitation and the Ganga itself. This topic covers the standards, rules and missions that make up India's environmental regulatory architecture — a heavily tested current-affairs area in GS-I.

General Studies Paper I Environment & Ecology 12%–15% weightage

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1Air & Water Pollution Standards

Two landmark laws — the Water Act (1974) and Air Act (1981) — created the CPCB, the body whose standards (NAAQS, AQI, water quality classes) define what counts as 'polluted' in India.

Learning Objectives

State the years and purpose of the Water (Prevention and Control of Pollution) Act and the Air (Prevention and Control of Pollution) Act.
Explain the role of the Central Pollution Control Board (CPCB) and State Pollution Control Boards.
List the six AQI categories from Good to Severe and the pollutants it tracks (PM2.5, PM10, SO2, NOx, CO, O3).
Explain the CPCB's water quality classification (Class A-E) by designated best use.

Key Terms

CPCBCentral Pollution Control Board — the apex statutory body (under the Water Act, 1974) that sets national pollution standards and coordinates State Pollution Control Boards.

NAAQSNational Ambient Air Quality Standards (2009) — CPCB-set permissible limits for 12 pollutants including PM2.5, PM10, SO2, NOx, CO, ozone and lead.

AQIAir Quality Index, launched by CPCB in 2014; a single 0-500 scale (Good to Severe) built from real-time readings of eight key pollutants.

GRAPGraded Response Action Plan — emergency measures (construction bans, vehicle restrictions) triggered as Delhi-NCR's AQI crosses successive severity thresholds.

India's pollution-control architecture rests on two foundational laws that both predate the 1986 Environment (Protection) Act: the **Water (Prevention and Control of Pollution) Act, 1974** and the **Air (Prevention and Control of Pollution) Act, 1981**, each of which empowers the Central Pollution Control Board (CPCB) and State Pollution Control Boards to set and enforce standards.

Measuring air quality

The CPCB's **National Ambient Air Quality Standards (NAAQS, 2009)** set permissible limits for 12 pollutants. Since 2014, these readings feed into the **Air Quality Index (AQI)**, a single 0-500 number in six bands: Good (0-50), Satisfactory (51-100), Moderate (101-200), Poor (201-300), Very Poor (301-400) and Severe (401-500).

Key PointDelhi-NCR's Graded Response Action Plan (GRAP) escalates restrictions — dust control, then construction bans, then vehicle restrictions — as AQI crosses each successive threshold, most aggressively in the Severe band.

Measuring water quality

CPCB classifies water bodies into five classes (A to E) by their 'designated best use' rather than raw pollutant levels — Class A water can be treated for drinking with only disinfection, while Class E is fit only for irrigation or industrial cooling.

Common MistakeExam trap: 'Class A' water quality does NOT mean the water is currently drinkable without any treatment — it means it CAN be made potable using only conventional disinfection, without needing full advanced treatment.