New Delhi: On Saturday, amid the Diwali celebrations, the firecracker ban in Delhi went up in smoke with people flouting it with impunity.
According to a report published by a Delhi-based news organisation Times of India, the sound of crackers could be heard during the day and its intensity rose after 6: 00 pm and continued throughout the night at some locations.
The report said that average hourly PM 2.5 concentration in Delhi touched 910 micrograms per cubic metre (g/m3) at midnight, over 15 times the safe standard, before falling due to an increase in wind speed. While the overall Air Quality Index (AQI) touched “severe” on Diwali day with a reading of 414, it was recorded at 435 on Sunday.
In terms of AQI, this was Delhi’s worst Diwali since 2016, when a reading of 431 was recorded and 445 the day after, data from both Central Pollution Control Board (CPCB) and System of Air Quality and Weather Forecasting And Research (SAFAR) showed.
Last year, an AQI of 337 (very poor) was recorded on Diwali day, which marginally rose to 368 (very poor) the next day. A bigger spike was seen in 2018 when AQI rose from 281 (poor) on Diwali day to 390 (very poor) the next day owing to firecrackers, the report said.
SAFAR had forecast pollution to touch the “severe” level the day after Diwali even if no firecrackers were burst. It said additional emissions through firecrackers and crop stubble led to hourly PM2.5 concentration crossing more than 1,000 g/m3 at several locations across Delhi.
CPCB data showed that pollution peaked between midnight and 1am. AQI rose gradually from 414 (severe) at 4pm to 446 by 8pm and 460 by 1am. “This year, Diwali was celebrated in mid-November with unfavourable meteorological conditions for dispersal of pollutants compared with 2019 when the festival was in the last week of October,” added CPCB.
“The surface temperature was the lowest in the past five years, which might have contributed to more inversion conditions and lowest average mixing height, which limits vertical dispersion. Wind speed on both pre-Diwali and Diwali day were similar. Overall, this Diwali witnessed higher background levels of pollutants and further addition of particulates during night from firecrackers,” CPCB stated.
However, the wet weather have brought some relief from the pollution.
Quoting Kuldeep Srivastava, scientist at IMD and head of Regional Weather Forecasting Centre, the report said: “Easterly winds with speed ranging from 18 to 24 kmph were recorded, which helped in dispersal of pollutants. The rain also helped in settling some pollutants.”