Why did the Delhi air pollution levels fall quickly?

Experts attribute the relatively quicker fall in pollution levels to higher wind speed and temperature, which helped disperse the pollutants.

What concerns were raised about the Delhi Pollution Control Committee's (DPCC) air quality data?

Activists questioned the authenticity of the official data as several data points were missing during the peak pollution hours between 11 PM and 3 AM, when PM2.5 levels crossed 1,700 micrograms per cubic meter.

Home / Environment / Delhi Chokes as Diwali Fireworks Breach Pollution Limits

Delhi Chokes as Diwali Fireworks Breach Pollution Limits

Q: What was the air pollution level in Delhi during Diwali?

The air pollution in Delhi spiked to 100 times the World Health Organisation's (WHO) permissible limits on Diwali night as residents continued bursting firecrackers past the 10 PM deadline.

22 Oct

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Summary

Air pollution in Delhi spiked to 100 times WHO limits on Diwali night
Official air quality data went missing during peak pollution hours
Meteorological factors like wind speed helped quickly disperse pollutants

Delhi Chokes as Diwali Fireworks Breach Pollution Limits

According to official data, air pollution in Delhi spiked to 100 times the World Health Organisation's (WHO) permissible limits on Diwali night as residents continued bursting firecrackers well past the 10 PM deadline set by the Supreme Court. However, the pollution levels fell quickly, which experts attribute to higher wind speeds and temperatures.

The Delhi Pollution Control Committee (DPCC) data showed several missing data points for the peak pollution hours between 11 PM and 3 AM on the intervening night of Monday and Tuesday. This led environmental activists to question the authenticity of the official air quality reporting. For instance, PM2.5 levels in some areas crossed 1,700 micrograms per cubic meter, over 116 times the WHO limit, but the data was unavailable during the worst hours.

Experts suggest that moderately high wind speeds of 5-10 km/hr around midnight helped quickly disperse the pollutants. As Diwali was celebrated earlier than usual this year, the temperatures had not dropped drastically, further aiding the ventilation. However, the missing data has led to concerns that the actual air quality index (AQI) may have been underestimated by the authorities.