Delhi's air quality to get better from today

NEW DELHI: A sharp drop in temperature over the last 48 hours and a reduction in wind speed saw Delhi’s air quality deteriorate sharply on Thursday — the day after Diwali. The air was laden with a cocktail of pollutants.

System of Air Quality and Weather Forecasting and Research (SAFAR) on Thursday classified the air quality as “severe plus”, which is beyond a reading of 500 on the index. However, SAFAR forecast improvement in the next two days with AQI returning to “very poor” on account of an increase in surface wind speed.

“At 1am on November 8, the smoke layer became thick and started to trap pollutants near the surface rapidly and AQI entered the severe category by 2am. However, air quality is recovering from the afternoon and is likely to touch the ‘very poor’ range by night, provided no firecracker emissions are added,” said SAFAR in its analysis on Thursday.

The agency added, “Surface winds are playing a major role. The contribution of stubble fire appears to be marginal and PM2.5 in PM10 increased from 50% (normal) to 70% on Diwali night, indicating an increased share of locally-generated pyrotechnic emissions.”

Forecasts show AQI dropping to 398 (very poor) on Friday with a further drop to 361 (very poor) on Saturday.

Initial forecasts had stated that Delhi’s air quality would touch “severe” if even 50% of the firecrackers used in 2017 would be burst. “The moisture in the air is now normal and the holding capacity has reduced. The wind direction is south-westerly, but the inversion layer height is low. This helps in particulate matter getting accumulated. If no fresh pollutants are added and surface wind speed increases, air quality should improve from Friday,” said a SAFAR scientist.

Meanwhile, Bhure Lal, chairman of the Supreme Court-appointed Environment Pollution (Prevention and Control) Authority, said they were closely monitoring Delhi’s air quality. “We expected the air quality to hit severe again, which is why the ban on entry of trucks between November 8 and 10 was imposed. The situation is being monitored and if it stays severe for long, an emergency meeting could be called for additional measures,” Lal added.