Why in the News
A report by the Centre for Research on Energy and Clean Air (CREA) analysing Central Pollution Control Board (CPCB) data found that 204 out of 238 Indian cities exceeded national air quality standards during winter 2025–26.
| Centre for Research on Energy and Clean Air (CREA)Centre for Research on Energy and Clean Air (CREA) is an independent international research organisation that focuses on energy, air pollution, and climate change analysis. It is widely cited in global media and policy discussions for its data-driven assessments of fossil fuel use, emissions, and air quality impacts. |
Key Findings of the Report
- Most Polluted Cities
- Top cities with the highest PM2.5 concentration: Ghaziabad – 172 µg/m³, Noida – 166 µg/m³, and Delhi – 163 µg/m³
- Other highly polluted cities include: Greater Noida, Bahadurgarh, Dharuhera, Gurugram, Bhiwadi, Charkhi Dadri, and Baghpat.
- Most cities in the top 10 are from Uttar Pradesh and Haryana.
- Megacity Air Pollution Levels
- Average PM2.5 concentrations in major Indian cities:
- Delhi – 163 µg/m³
- Kolkata – 78 µg/m³
- Mumbai – 48 µg/m³
- Chennai – 44 µg/m³
- Bengaluru – 39 µg/m³ (slightly below national limit)
- Cleanest City
- The cleanest city recorded was: Chamarajanagar – 19 µg/m³
- Eight of the ten cleanest cities were in Karnataka, with one each in Madhya Pradesh and Meghalaya.
PM2.5 Explained
PM2.5 (Particulate Matter ≤2.5 micrometers)
- Extremely fine particles in the air.
- Can enter lungs and bloodstream.
- Causes: Respiratory diseases, Heart disease, and Premature deaths.
Prelims Pointers
- CPCB functions under the Ministry of Environment, Forest and Climate Change.
- National Ambient Air Quality Standards (NAAQS) specify permissible pollutant levels in India.
- PM2.5 is considered one of the most dangerous air pollutants due to its ability to penetrate deep into the respiratory system.
| [2022] In the context of WHO Air Quality Guidelines, consider the following statements: The 24-hour mean of PM2.5 should not exceed 15 µg/m³ and annual mean of PM2.5 should not exceed 5 µg/m³. In a year, the highest levels of ozone pollution occur during the periods of inclement weather. PM10 can penetrate the lung barrier and enter the bloodstream. Excessive ozone in the air can trigger asthma. Which of the statements given above are correct? (a) 1, 3 and 4 (b) 1 and 4 only (c) 2, 3 and 4 (d) 1 and 2 only |
