Delhi’s air quality reaches dangerous levels

Air quality in the national capital oscillated between “severe” and “very poor” levels with pollutants rising exponentially and noise pollution peaking owing to incessant fireworks and bursting of crackers on Diwali night.

The intensity of air pollution on Diwali night was “less” compared to last year, presumably due to wind movement, as per Centre for Science and Environment (CSE). The Delhi government attributed the reduction to its anti-firecracker campaign.

System of Air Quality and Weather Forecasting and Research (SAFAR), which observed air quality of the “Diwali period” of last three days, said the city was “more polluted” than last year. It said the overall levels of PM 2.5 and PM 10 were 258 and 386 micrograms per cubic metre on Wednesday night.

It identified Palam, Delhi University, Pitampura and Noida as the leading pollution spots with corresponding PM 2.5 readings at 344, 275, 281 and 302 respectively.

SAFAR, a ministry of earth sciences entity, said air quality in number of areas was “severe” which means the level of PM 2.5 and PM 10 were above 253, 421 micro gram per cubic metre. “Severe” is used to describe the highest level of pollution.

As per the Delhi government, whose analysis was based on “ambient air quality” (outdoor air quality over long-term) data of six stations, maximum average values of sulphur dioxide, nitrogen dioxide and PM 2.5 were lower at these locations on this Diwali compared to their corresponding values on the occasion of Diwali in 2014.

The Delhi Pollution Control Committee (DPCC) stations are located at R.K. Puram, Mandir Marg, Punjabi Bagh, Civil Lines, Anand Vihar and IGI Airport.

The Delhi government attributed the reduction to people’s positive response to its anti-firecrackers campaign, involving chief minister Arvind Kejriwal among others. CSE said it was due to comparatively less crackers and mild wind in some parts.

“The recorded wind speed during 2015 Diwali was 1.19 metre per second in contrast to 0.62 m/s in 2014 — the wind speed in this Diwali had almost doubled,” a CSE statement said.

But the NGO claimed that its exposure monitoring, essentially the level of pollution within breathing zone at the time crackers were burst, threw up figures showing “alarming levels of exposure”.

Even the Delhi government claimed the pollution level on the Diwali night was less than last year, however, experts said it was too early to draw a conclusion.

“People breathed several times higher pollution than the ambient level monitored by DPCC. Overall, during Diwali evenings people breathed an hourly average that is at least 3 to 4 times higher than the ambient monitoring recorded at the DPCC stations,” the CSE said.

As per Delhi government, 24 hours average of PM 2.5, which are finer and more harmful to those susceptible to ailments of the respiratory tract, ranged from 184µg/m3 to 369 µg/m3 on November 11.

The minimum was observed at Civil Lines and maximum at R.K. Puram. On Diwali Day in 2014, the average concentration (for 24 hrs) for PM 2.5 ranged from 145 µg/m3 to 500 µg/m3, the government said.

Areas scattered across the megapolis saw alarming levels of pollution in the night with Anand Vihar, R.K. Puram, Mandir Marg, Punjabi Bagh breaching all safety standards in terms of both air and noise pollution.