Delhi faces its worst smog in 17 years

CSE experts say that as per the India Meteorological Department, the smog on Nov 2, 2016, was the worst in 17 years.

Speaking on the issue, Anumita Roychowdhury, executive director (research and advocacy), CSE and head of CSE’s air pollution and sustainable mobility teams, said, “This demands emergency response to protect the vulnerable – those who are suffering from respiratory and heart diseases and children. The government should aggressively inform all and advise them to stay indoors and avoid outdoor exercises. At the same time, it should roll out stringent winter pollution control for all sources along with emergency action.”

Post-Diwali peak of pollution is higher than the Diwali peak.

The analysis of data from Delhi Pollution Control Committee shows that the levels of PM2.5 have increased by 62.7 per cent on Nov 2 as compared to that on Diwali.

On Nov 2, the levels were 9.4 times the standard.

On the night of Nov 1, (12 am to 6 in the morning of Nov 2), the PM2.5 concentration had hit 548 microgramme per cubic metre (cu m), which is nine times the standard.

The following day (Nov 2), PM2.5 concentration (6 am to 12 noon) increased to 696.25 microgramme per cu m, 11.6 times the standard.

The morning concentration was 27.1 per cent higher compared to the night time concentration.

The hourly averages were as high as 800-900 microgramme per cu m.

According to SAFAR, the PM2.5 levels are in severe category and are expected to remain in this category for more than three days.

According to the Indian Meteorological Department, this is the worst smog with very poor visibility in 17 years.

The Indira Gandhi International Airport in Delhi recorded the worst levels of smog in 17 years on Nov 2, with visibility as low as 300-400 metres.

The period between 11 AM and 2:30 PM was the worst in the day with respect to airport visibility.

The post-Diwali smog reduced the visibility there to 800-1,200 m since Oct 30.

Pollution during Diwali, other sources of pollution along with weather-related factors lead to such abnormal levels.

Meteorological scientists explain that lower level anticyclone, a weather phenomenon which prevented the dispersion of smog, developed around Delhi on Nov 2, 2016. 

There was virtually no wind in the vertical column.

This situation is expected to persist for few more days.

The Central Pollution Control Board has already warned that the average wind speed this year on Diwali day was much less, about 1.3 m/s compared to last year’s 3.4 m/s.

Also, the mixing height this year was 492 meters whereas in 2015 it was 590 meters.

The lower wind speed and mixing height do not allow wind to disperse quickly leading to higher concentration of pollutants.

Satellite images of NASA’s fire mapper have showed that incidences of paddy burning in Punjab, Haryana and Uttar Pradesh have increased after Diwali.

The images clearly revealed that after Oct 30, 2016, crop burning in Punjab, Haryana and Uttar Pradesh became more aggressive which would have contributed to the severe smog in the national capital.

“Delhi needs strong action to protect people from such deadly exposure. Immediately step up action and put out hard health evidences and heath alerts in the public domain to sensitise people about the harmful effects of smog and push action. Delhi needs an effective winter pollution mitigation plan that can make a difference. Without strong action smog is only expected to get worse this winter at serious public health costs,” Roychowdhury said.