As mercury dips suddenly and a heavy layer of smog engulfs Delhi and NCR on Thursday,the national capital remained shrouded in a cover of thick smog, laden with high level of pollutants which kept air quality in the ‘severe’ category, four days after Diwali festivities.
Hostile weather conditions like cool temperature and nearly zero wind movement were the major factors identified by experts for pollution level continuing to be on the higher side.
The peak levels of pollution (PM2.5 and PM10), recorded over ten times the safe limit during the morning hours, gradually came down across monitoring stations as the day progressed. The safe limits of these microscopic particles are 60 and 100 micrograms per cubic metre respectively.
“Wind is very calm and the temperature is only turning colder. All that is leading to trapping of pollutants near the surface. But this happens every winter, the intensity may differ. Delhi is truly a gas chamber now,” Anumita Roychowdhury of Centre for Science and Environment (CSE) said.
She said the MeT department had forecast well ahead of Diwali that wind movement would peter out from October 29. It had led to a phenomenal build up of pollutants, she said.
“Studies have shown that the pollutants from fireworks linger on for at least 24 hours. And firecrackers were burst well into last night. And moreover, these pollutants will enter the food chain once they settle down,” she said.
The 24-hour average of PM2.5 and PM10 were 348 and 522 micrograms per cubic metre respectively, as per SAFAR. AQI will be severe tomorrow as well, its forecast said.
SAFAR had forecast that air quality was likely to improve slowly from November 2 but all its monitoring centres in the city recorded severe quality air in the evening hours.
Central Pollution Control Board (CPCB) stations in Mandir Marg, Punjabi Bagh, Anand Vihar, RK Puram and Dwarka also recorded severe air quality.
Prolonged exposure to severe category air may affect healthy people and seriously impact those with existing diseases while very poor category may cause respiratory illness. Children, elderly and the sick are considered most vulnerable to the harmful effects of hazardous air.