Air pollution

Topic: Environment and Sustainable Development · NCERT: Class 11, Ch 7 "Environment and Sustainable Development"

Meaning

Air pollution is the contamination of air by harmful gases and tiny particles (particulate matter) from vehicles, industry, thermal power plants and the burning of biomass (crop waste, wood).

It matters because it is one of NCERT's five priority environmental issues for India, where vehicular pollution in cities is singled out. It also imposes a heavy cost on health and on GDP.

NCAP target formula: % reduction in PM10 = (PM10 in 2017-18 − PM10 in 2025-26) ÷ PM10 in 2017-18 × 100

Explanation

What pollutes the air: PM10 and PM2.5

• Particulate matter (PM) means tiny solid or liquid bits floating in the air.
• PM10 has a diameter below 10 micrometres.

• PM2.5 has a diameter below 2.5 micrometres.

• The smaller the particle, the deeper it goes into the lungs. So PM2.5 does more harm than PM10.

• Harmful gases come from burning fuel, such as coal in power plants and petrol or diesel in vehicles.

The main sources

• Vehicles (vehicular pollution)
• Vehicles release smoke at ground level, where people breathe.
• Smoke from tall factory chimneys spreads out before it reaches people. Vehicle smoke does not get that chance.

• So city residents take in a larger dose.

• Industry (industrial pollution)

• Factories release emissions (harmful smoke) and effluents (liquid waste).
• India is among the ten most industrialised nations.
• CPCB lists 17 categories of highly polluting industries.

• NCERT calls the Damodar valley an "ecological disaster" because coal, steel and power industries are packed together there.

• Thermal power plants, which burn coal.

• Stubble burning: after the harvest, farmers burn the crop stalks left in the field. This happens mainly in Punjab and Haryana before winter.

Why it keeps rising: pollution from affluence

• India faces pollution from affluence (harm caused by richer consumers and fast growth):

• incomes rise → people buy more vehicles, and more factories and power plants come up → more smoke and waste.

• Worked example: growth in vehicles

• Vehicles grew from ~3 lakh (1951) to 35 crore (2022).
• 35 crore ÷ 3 lakh = 3,500 lakh ÷ 3 lakh ≈ 1,167 times in about 70 years.

• Two-wheelers and cars made up ~85% of registered vehicles.

• Poorer countries usually face poverty-related damage first and pollution later. India faces both at the same time, with limited money to fight either.

Worked example: reading an NCAP target

• A city's PM10 falls from 150 µg/m³ (2017-18) to 90 µg/m³ (2025-26).
• % reduction = (150 − 90) ÷ 150 × 100 = 40%, so it has met the 40% target.
• But 90 is still above the NAAQS limit of 60 µg/m³ (annual PM10). NAAQS means National Ambient Air Quality Standards, the legal safe limits for outdoor air.
• This is why the target reads "up to 40% or NAAQS": a very polluted city can meet the percentage cut and still have unsafe air.

In India

• CPCB (Central Pollution Control Board)
• Set up in 1974 under the Water (Prevention and Control of Pollution) Act.
• Got its air-pollution powers under the Air Act 1981.
• SPCBs (State Pollution Control Boards) do the same work in the States.

• The boards set emission standards, inspect industries through district-level officials, and provide air-quality data. This data is used to decide where industries can be located and to plan towns.

• Policy timeline

• 2014: National Air Quality Index (AQI). It turns pollutant levels into one number and colour band that the public can read.
• 2017: GRAP (Graded Response Action Plan). Emergency steps for Delhi-NCR that get stricter as AQI worsens, for example halting construction.
• January 2019: NCAP (National Clean Air Programme). India's first national, time-bound clean-air programme.

• 2021: CAQM Act. It created the Commission for Air Quality Management for NCR and adjoining areas.

• NCAP in detail

• Launched by MoEFCC. It covers 130 cities in 24 States/UTs, and each city has its own clean air action plan [2].
• The cities are non-attainment cities (cities that failed to meet NAAQS for five years in a row) and million-plus cities.

• Target: cut PM10 by up to 40%, or meet NAAQS, by 2025-26, against the 2017-18 base [2].

• NCAP results, 2025-26 vs 2017-18 [3]

• 108 cities recorded lower annual PM10.
• 72 cities cut PM10 by more than 20%.
• 26 cities cut PM10 by more than 40%.

• 14 cities met NAAQS for PM10 (annual limit ≤ 60 µg/m³), up from 6 in 2017-18 [3].

• Cost: Lancet Planetary Health (estimates for 2019) put the toll at ~1.67 million deaths and ~1.4% of GDP lost. This is not an official government figure.

Don't confuse with

• PM10 vs PM2.5: NCAP's target is based on PM10, not PM2.5. PM2.5 is smaller and more harmful because it goes deeper into the lungs.
• NCAP vs GRAP: NCAP (2019) is a national, long-term programme for 130 cities. GRAP (2017) is an emergency plan only for Delhi-NCR that is triggered by AQI levels.
• AQI vs NAAQS: AQI (2014) is a public information index, one number plus a colour. NAAQS is the legal standard, the safe limit each pollutant must stay under.
• Pollution from affluence vs poverty-induced degradation: air pollution comes mainly from rising incomes (more vehicles, factories, power). Poverty-induced degradation comes from poor people overusing land, forests and fuelwood to survive.

Prelims Hooks

• NCERT's five priority issues include air pollution, "especially vehicular pollution in cities". Vehicles harm people most because they emit at ground level.
• CPCB, 1974 was set up under the Water Act. Its air powers came later, from the Air Act 1981. Trap: CPCB did not start as an air body.
• NCAP (January 2019, MoEFCC) covers 130 cities in 24 States/UTs. Its target is a PM10 cut of up to 40% or meeting NAAQS by 2025-26, against the 2017-18 base [2].
• By 2025-26, only 14 NCAP cities met the PM10 NAAQS (annual ≤ 60 µg/m³), while 108 cities recorded lower PM10 [3].
• CAQM was created by an Act in 2021 for NCR and adjoining areas. GRAP dates from 2017. AQI dates from 2014.
• NCERT calls the Damodar valley an "ecological disaster". CPCB lists 17 categories of highly polluting industries.

Mains Points

• Results vs targets under NCAP
• Progress is real: 108 of 130 cities cut PM10, but only 14 reached safe NAAQS levels [3].

• Weak points:

  • it targets PM10 and not the more harmful PM2.5
  • SPCBs lack enough staff and enforcement power
  • a percentage cut can hide air that is still unsafe

• Pollution crosses borders, so control must too

• Stubble burning in Punjab and Haryana → smoke drifts into Delhi-NCR → no single city can fix its own air.

• This is why an airshed body (one authority for the whole area that shares the same air), the CAQM (2021), was needed on top of city plans.

• Growth vs clean air

• Rising incomes bring more vehicles and industry, so air pollution is a cost of affluence.
• The fix is regulation and pricing, such as emission standards and the polluter pays principle (whoever pollutes pays for the damage). Policy must still keep clean growth pro-poor, for example by protecting farmers' incomes while ending stubble burning.

Related concepts

• Poverty-induced degradation and pollution from affluence
• Land degradation
• Deforestation
• Soil erosion
• Open access resource
• Biodiversity loss
• Industrial pollution
• Water pollution
• Groundwater overuse
• Virtual water

Read more

• State of India's environment: the dichotomy and the five priority issues