The Capital witnessed the worst Diwali in three years in terms of air quality as a deadly cocktail of harmful pollutants and gases engulfed the city in thick smog.
Monitoring agencies — Delhi Pollution Control Committee (DPCC), Central Pollution Control Board, Pune-based SAFAR and Centre for Science and Environment — were unanimous about the foulness of the city’s air.
The most polluted corner on Diwali night was Anand Vihar with 888µg/m³ of particulate matter (PM) 2.5 at 1 am. PM10 was 1,684 µg/m³ at 2 am, according to DPCC.
PM 10 fluctuated between 448 µg/m3 and 939 µg/m3 on Sunday. On Diwali in 2015, it was between 296 µg/m3 and 778 µg/m3. In 2014, it ranged from 421 µg/m3 to 790 µg/m3, according to DPCC data.
On Monday, the city woke up to the season’s worst air quality as smoke from Diwali fireworks, coupled with moisture and nearly stagnant winds.
System of Air Quality and Weather Forecasting and Research (SAFAR), an agency under the earth sciences ministry, said air quality was not only severe but plunged to its worst in three years during Diwali mainly due to low wind movement and falling boundary layer that traps pollutants close to the surface. The most critically polluted period was between 11pm on October 30 and 10am on Monday.
On Monday morning, the 24-hour rolling average of PM10 and PM2.5 were 700 and 450 respectively, according to SAFAR data. “The AQI overall across the city is 500+ and will remain similar even on Tuesday. Low wind speed and temperature are the reasons behind this,” SAFAR project director, Gufran Beig said.
SAFAR said the Delhi University area was the most polluted while Ayanagar was the least polluted. On the other hand, DPCC showed Anand Vihar as the most polluted in terms of both PM 2.5 and PM 10.
In its report, the Centre for Science and Environment said this year Diwali pollution was not only worse but also more toxic as maximum levels of several gases and particles have gone up from last year.
CSE said the minimum and maximum levels of nitrogen oxide this year was 70-123 microgramme per cubic metre compared to 37-79 microgramme per cubic metre in 2015.
“The maximum levels have increased by nearly 1.5 times. The lower level has doubled. CO levels, that otherwise is declining in Delhi increased during this year compared to last year. High level of CO can curdle blood and lead to instant deaths,” it said.
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