A day after Diwali: ‘Very poor’ air in Ggm, experts say data is faulty

GURUGRAM: A day after Diwali, the city’s air quality veered into the “very poor” category for the first time this season, with 372 on the Central Pollution Control Board’s air quality index (AQI) bulletin. At 4pm on Monday, the average 24-hourly concentration of PM2.5 stood at 370ug/m3, more than six times the safe limit of 60ug/m3 (as per the National Ambient Air Quality Standards), and 37 times the World Health Organization’s safe limit of 10ug/m3.

This is up from 299 (poor) the previous day, according to data from the Haryana State P ollution Control Board’s only air monitor in the city at Vikas Sadan.

However, experts and officials both said that the AQI of 372 was erroneous, and that Gurugram has seen its “cleanest” Diwali in at least four years despite residents burning crackers deep into the night. “The data from the air quality monitor must be wrong, or the way the AQI is being calculated is wrong. It is done automatically and might need some correction,” said Rajesh Garhia, senior scientist, HSPCB.

Experts also concurred with Garhia’s claim that the data was either incorrect or mistakenly represented. Sachin Panwar, a city-based air quality scientist, said, “This time, we have recorded an average concentration of PM2.5, which is the most prominent pollutant in the city, lesser than last Diwali. Last year, we saw PM2.5 matter concentration touching as much as 4,079ug/ m3 in certain areas. This year, based on data from the same hotspots in Manesar, Udyog Vihar and Sector 81, we have seen averages between 2,800ug/m3 to 3,000ug/m3.”

Panwar added that favourable meteorology was the underlying reason for this year’s dip in postdiwali pollution. “We had strong winds blowing on Sunday night, as well as on Monday morning that helped to disperse some pollutants,” said Panwar.