Across India, 70% of Stations Reported ‘Severe’ PM2.5 Readings, Pg7

Key Highlights:

• Nearly 70% of India's Continuous Ambient Air Quality Monitoring Stations (CAAQMS) reported 'severe' PM2.5 levels during Deepavali.
• Out of 551 reporting stations, 375 recorded PM2.5 values of 250 micrograms per cubic metre or more at least once during Deepavali.
• The Central Pollution Control Board (CPCB) stated that data gaps occurred when PM2.5 values exceeded the 1,000 micrograms per cubic metre analyser calibration limit.
• States including Maharashtra, Uttar Pradesh, Rajasthan, Haryana, Madhya Pradesh, Gujarat, and Andhra Pradesh also experienced widespread severe pollution.
• Sulphur Dioxide (SO2) levels in Delhi, Mumbai, and Kolkata showed no significant drop, questioning the effectiveness of green crackers.

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Detailed Insights:

• The analysis covered 634 CAAQMS in the CPCB network, focusing on the Deepavali period from November 7 (5 p.m.) to November 9 (5 a.m.).
• Only 571 of the 634 stations were live and reporting data during Deepavali, indicating potential operational issues within the monitoring network.
• The number of stations reporting 'severe' PM2.5 significantly increased from 96 in the pre-Deepavali window to 375 during Deepavali.
• Tamil Nadu showed a notable absence of data, with only 9 out of 37 stations reporting PM2.5 levels at least once during the hourly windows.
• The CPCB clarified that its automated data validation system ignores values outside the 1,000 micrograms per cubic metre range, leading to apparent data gaps during extreme pollution episodes.
• The consistent SO2 levels in major cities suggest that the intended environmental benefits of 'green crackers' in reducing gaseous emissions may not be fully realized.

Key Concepts Involved:

• PM2.5: Fine particulate matter with a diameter of 2.5 micrometers or less, capable of penetrating deep into the lungs and bloodstream.
• Continuous Ambient Air Quality Monitoring Stations (CAAQMS): Automated systems that continuously measure and record various air pollutants in real-time.
• Central Pollution Control Board (CPCB): A statutory organization under the Ministry of Environment, Forest and Climate Change, responsible for pollution control and monitoring in India.
• Severe Air Quality: An air quality category where PM2.5 concentrations are 250 micrograms per cubic metre or above, indicating serious health impacts.