Delhi pollution data gap: 125 missing PM2.5 readings all above 1,000 µg/m³

The Delhi Pollution Control Committee (DPCC) has released the air quality data that had gone missing on Diwali night. They show pollution well above what official records reflected. The DPCC published the delayed hourly data around 8 pm on Monday, and every one of the 125 station-hours absent from Central Pollution Control Board (CPCB) records read above 1,000 micrograms per cubic metre. At one location, the concentration of PM2.5 was above 3,744 micrograms per cubic metre, which is 60 times above the national average.

The missing data paints a distressing picture of the Diwali night. Mundka recorded the highest PM2.5 concentration, 3,744 µg/m³, followed by Jawaharlal Nehru University at 3,023 µg/m³ at 4 am. The NSUT West Campus station recorded 3,008 µg/m³ at 5 am. 11 of the DPCC monitoring stations recorded PM2.5 concentrations above 2,000 µg/m³.

The gap surfaced after 36 of Delhi's 59 monitoring stations stopped reporting overnight into November 9, prompting the Aam Aadmi Party to allege "AQI data fraud" by the ruling BJP government. AAP MP Saurav Bharadwaj said that the pollution data was being manipulated to bring down the city's average air quality index.

Also Read: Erika Kirk slams 'moral decay' of Dave Chappelle for joking about Charlie Kirk's assassination

While only one station had missing data at 7 pm on Sunday, it increased to seven by 10 pm, 23 by 11 pm, 29 by midnight and 36 at 1 am. An analysis by the Centre for Research on Energy and Clean Air (CREA) said that across 59 stations, CREA counted 227 missing hourly observations between midnight and 5 am.

According to Anil Gupta, a member of the Delhi Pollution Control Committee, who told NDTV that when the reading reached "999, the monitoring station stops giving a reading." He called it a technical glitch. DPCC, 2019 technical specifications mandate that continuous particulate matter analysers must have a measuring range of 0 to 1,000 µg/m³.

But it doesn't explain why some stations dropped out at different levels. RK Puram's last reading was 924 µg/m. A single hard cutoff at 1,000 can't produce that, though the very next hour the reading may have crossed 1,000. There is no explanation of the mechanism or an established threshold of the system's configuration. An audit of the station firmware and the CPCB/DPCC data-validation rules could settle it. December 14, 2026, is the deadline set by the Supreme Court of India for comprehensive compliance reports and may be the first official account.