PM 2.5 levels worst in 3 years, says Delhi pollution committee

The panel also said the concentration of different pollutants such as SO2, CO and NO2 overall showed a decrease from last year, but the concentration was higher than in 2019

The Delhi Pollution Control Committee (DPCC), in its Diwali analysis on Friday said Delhi recorded an average PM 2.5 concentration of 607 micrograms per cubic metre on Diwali day – the highest in the last three years. It also said the concentration of different pollutants such as SO2, CO and NO2 overall showed a decrease from last year, but the concentration was higher than in 2019.

Commuters drive amid low visibility on Diwali at Narwana road as the pollution level rises, in New Delhi. (Raj K Raj/HT Photo)

“The sudden deterioration this year attributed to extremely calm conditions, change of wind direction extremely calm conditions and low ventilation co-efficient and use of firecrackers. Though the increase in trend in the concentration of pollutants like PM2.5 & PM10 was observed since the evening of the November 3, major changes were observed after 8:00 PM on Diwali when the fireworks started. Ambient Air Quality in Delhi was already in the ‘very poor’ category due to the accumulation of pollutants in the air shed,” said DPCC in its analysis on Friday, stating active fire counts this year were much higher than last year on Diwali day.

“On this Diwali day, the active fire count was recorded at 3383, while in 2020, the fire count on Diwali day was just 623,” it said.

DPCC says the highest PM 2.5 concentration was recorded at midnight, with pollution levels starting to dip after that, adding that Delhi’s average PM 2.5 concentration ranged from 315 µg/m3 to 960 µg/m3.

While the lowest average concentration was recorded at the National stadium, the highest average PM 2.5 concentration was seen at Jahangirpuri.

In terms of noise pollution, real-time noise monitoring was undertaken at 31 locations by the DPCC, finding decibels level ranges from 54.2 dB (A) at Wazirpur to 77.4 dB(A) at Karol Bagh on Diwali day. On a normal day, the range varies from 46.4 dB(A) to 69.5 dB(A).