Source:Times Of India
NEW DELHI: For the past three days, Delhiites have been breathing air that’s almost as noxious as the air during this year’s Diwali, indicating a rapid deterioration in pollution levels caused by local emissions and weather conditions.
The air quality index currently is in ‘very poor’ category, close to the ‘severe’ zone seen during Diwali – a level that triggers emergency measures, such as shutting down schools, in many countries. And unlike Diwali time, the contribution from farm fire in neighbouring states is very low.
Pollution has been rising since November 17, peaking to almost Diwali levels on November 21, 22 and 23, an analysis by SAFAR shows. These levels are worse than the same period last year and may remain high for a few more days.
While the PM 2.5 (fine, respirable pollution particles) levels were about 260 micrograms per cubic metre on Diwali day, pollution subsided because of moderate winds.
Now, relatively calm weather and dropping temperatures have brought down the boundary layer (lowest part of atmosphere), trapping pollutants near the surface. On November 21, the average PM 2.level was as high as 240 micrograms per cubic metre and on Monday it was about 220 micrograms per cubic metre, which is 3.6 times the national standard. Monday also saw a grey smog hanging over the city.
“There was no moisture in the air on November 21 and 22 which is why fog didn’t form. But now, some cold winds have brought in moisture which helps accumulate particulate pollutants, which is making it very smoggy,” said Gufran Beig, project director, SAFAR.
A study, commissioned to IIT Kanpur to identify local sources of pollution in Delhi, is yet to be made public. Ashwani Kumar, environment secretary told TOI that the department is likely to have a meeting with IIT scientists in December.