Delhi’s PM2.5 readings hit 1,000 on Diwali night before monitoring stations went blank

Millat Times Desk

09 November 2026 (Publish: 11:29 AM IST)

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PM2.5 levels at several Delhi air monitoring stations climbed close to 1,000 micrograms per cubic metre on Diwali night before the readings stopped, even as the stations continued reporting data for other pollutants, according to an analysis by the Hindustan Times of CPCB records.

The newspaper found that 43 of Delhi’s 59 monitoring stations had gaps in PM2.5 readings between 10 pm on November 8 and 6 am on November 9. At 14 stations, the last recorded reading before the gap was 900 µg/m³ or higher.

The HT analysis found that none of the stations recorded PM2.5 levels above 1,000 this year, unlike last Diwali, when 29 of 39 comparable stations recorded at least one hourly reading above that mark. The highest reading last year was 2,224 µg/m³ at NSIT Dwarka.

The newspaper also estimated Delhi’s AQI at 437 for the 24 hours ending 9 am on November 9, based on available readings. After accounting for missing hours, its estimate rose to 471. The CPCB’s official AQI at 9 am was 370.

HT said the apparent ceiling around 1,000 µg/m³ could be linked to the monitoring equipment or the CPCB’s data system. It said it had sent questions to the pollution watchdog seeking an explanation.