Delhi pollution monitors went dark as AQI surged on Diwali
PM2.5 readings at several monitoring stations went blank as smoke levels climbed towards 1,000 micrograms per cubic metre, according to Hindustan Times.
Air quality monitoring stations in Delhi experienced data gaps for PM2.5 readings on Diwali night as pollution levels rose, according to an analysis of Central Pollution Control Board (CPCB) records by the Hindustan Times. The missing data occurred as readings climbed towards 1,000 micrograms per cubic metre (µg/m³), which pulled down the official air quality index (AQI) for the following day.
The Delhi Pollution Control Committee (DPCC) released data on Monday evening showing that 125 station-hours missing from CPCB records were above 1,000. One station in Mundka recorded 3,744 µg/m³ at 2am. While PM2.5 data was missing, stations continued to send readings for other gases such as nitrogen dioxide, carbon monoxide and ozone.
A Delhi government official acknowledged a technical glitch but stated that all 43 stations were providing data. The CPCB did not provide an explanation for the outage. The missing hours resulted in a lower official AQI of 344 in the CPCB 4pm bulletin on Monday, whereas estimates including DPCC readings suggest the figure would have been approximately 360.
Urban Acres reported that Delhi's average AQI reached 368 on Monday morning, with several locations recording readings above 400. Visibility at Safdarjung Airport was recorded at 50 metres at 5.30 am. The deterioration followed firecracker use across Delhi-NCR on Sunday night, despite the Supreme Court permitting green crackers only between 8 pm and 10 pm.