NEW DELHI: The Delhi Pollution Control Committee released on Monday evening the hourly Diwali-night readings that had been absent from the Central Pollution Control Board's records, showing fine particulate matter at one station climbing to 3,744 micrograms per cubic metre. That is more than 60 times the 60-microgram limit that applies over 24 hours.
Mundka logged the highest concentration, at 2 am on Monday. Jawaharlal Nehru University followed with 3,023 at 4 am and the NSUT West Campus station with 3,008 at 5 am. Mandir Marg, Nehru Nagar and Wazirpur also crossed 2,000, at 2,908, 2,808 and 2,721 respectively, and 11 of the committee's stations went past that mark.
The release followed a day of questions about why readings vanished as the air deteriorated. At 1 am on Monday, only 23 of the capital's 59 monitoring stations were still reporting PM2.5 to the central board, with 36 showing no figure. The count of silent stations had climbed from one at 7 pm on Sunday to seven by 10 pm and 23 by 11 pm, touched 35 at 2 am, and fell to two by 9 am. An analysis by the Centre for Research on Energy and Clean Air put the number of non-reporting stations above 20 in the hours between midnight and 2 am.
The gap mattered because the missing hours covered the worst of the spike. Every one of the 125 station-hour readings that the central board's records lacked was above 1,000 in the committee's data, while the highest figure available centrally for the night was 1,000. Where both agencies had figures, they matched.
A government official blamed technical faults, saying the monitors were supplying hourly data. "There were some technical glitches, but all our 43 stations are giving data," the official said, even as the central board's records showed most stations silent at 1 am.
The capital had recorded an air quality index of 376 at 4 pm on Diwali day, November 8, its most polluted Diwali in five years. The post-Diwali index touched 370 at 11 am on Monday before improving to 344 by 4 pm. Fine particles are small enough to penetrate deep into the lungs and reach the bloodstream, and sustained exposure has been associated with respiratory and cardiovascular illness.
The figures have also fed a political row. The AAP's Saurabh Bharadwaj reportedly alleged that the BJP-led Delhi government had manipulated the data and shut stations during peak pollution, telling reporters the numbers were "based on fraud" and that water was being sprinkled over monitors in polluted areas. The BJP reportedly countered that the AAP had conspired to keep pollution high in the capital by encouraging stubble burning in Punjab, with Delhi Minister Kapil Mishra citing about 1,200 such incidents in the State on Sunday.
(With inputs from media reports)