With the governments in Delhi and neighbouring States blaming each other for heavy smog over the Capital, the System of Air Quality and Weather Forecasting and Research (SAFAR) on Tuesday said that crop burning in the NCR accounted for only 18 per cent of the pollution in the city in the last 24 hours.
As per SAFAR, the effect of crop burning in neighbouring States on Delhi’s pollution fell on Tuesday due to the wind pattern.
The 24-hour rolling average of PM2.5 was 295 micrograms per cubic metre (ug/m3) — four times the safe limit of 60 ug/m3 — as of 7.30 p.m. This was still ‘severe’, but relatively better than the peaks of 14 to 16 times the safe limits witnessed post-Diwali.
The level of PM10 was 474 ug/m3 — four times the safe limit of 100.
That being said, the National Air Quality Index showed highly toxic levels of pollution across the city.
Sources of pollution
The AQI showed ‘severe’ pollution in Anand Vihar, IHBAS (Dilshad Garden), Mandir Marg, R.K. Puram and Punjabi Bagh, and ‘very poor’ in NSIT Dwarka.
Using modelling techniques, SAFAR came up with the potential contribution of different sources of pollution.
“From November 1, when the contribution of crop burning was nil to November 6, when the contribution went up to 70 per cent, the amount differs depending on the wind,” said a SAFAR official. For instance, the contribution of crop burning to pollution was 40 to 50 per cent on Monday, but fell to 18 per cent on Tuesday.
As per an IIT-Kanpur study on sources of pollution in Delhi, during winter, bio-mass burning accounts for 17 per cent of PM10 and 26 per cent of PM2.5 pollutants.
With the smog lifting on Tuesday, the South Delhi Municipal Corporation announced that it would be opening its primary schools from Thursday. Earlier, the SDMC had announced its schools would remain shut till November 15.
Contribution of crop burning went up
from nil on November 1 to 70 per cent
by November 6