Pollutants from west Asia triggered Delhi’s haze, says Met

Experts from SAFAR, which is maintained by the Union ministry of earth sciences, said that a major portion of the pollutants that triggered the three-day haze had come from west Asian countries like Iraq, Kuwait and Saudi Arabia.

Pollution levels in Delhi-NCR, that had breached emergency levels on Tuesday and continued to deteriorate over the next two days, improved significantly on Friday.

Smog engulfs India Gate on Friday morning. (Ravi Choudhary/HT PHOTO)

With wind speed expected to pick up from Saturday, the air quality is likely to return to the pre-haze level of ‘very poor’ by Sunday night.

Experts from SAFAR, which is maintained by the Union ministry of earth sciences, said that a major portion of the pollutants that triggered the three-day haze had come from west Asian countries like Iraq, Kuwait and Saudi Arabia.

“These pollutants were transported to Delhi and other parts of northwest India by strong-velocity high-altitude winds coming from west Asia. This, along with pollutants from stubble burning regions of Punjab and Haryana, pushed up the pollution levels in Delhi,” said Gufran Beig, project director of SAFAR.

The Air Quality Index (AQI) of Delhi dropped marginally from 486 on Thursday to 468 on Friday. Experts said that since AQI was a 24-hour average and took into consideration high pollution levels of Thursday night too, the actual improvement was not reflected.

CPCB data says that the PM10 level, which was hovering above 880 ug/m3 on Wednesday night and Thursday morning, dropped to 540 ug/m3 by Friday night. PM10 values above 500 denote emergency levels.

Similarly PM2.5 levels, which had crossed 600 ug/m3 on Wednesday night, came down to 389 ug/m3 by Friday night. PM2.5 values above 300 denote emergency levels.

“The situation has improved significantly compared to what it was on Tuesday and Wednesday. We are expecting further improvements on Saturday and Sunday,” said an official of the regional weather forecasting centre.

Met officials said that surface level winds, which would help to flush out the pollutants from Delhi’s air, are still calm as an anti-cyclonic circulation is located over northwest India. This system is likely to weaken by Saturday allowing surface level winds to pick up speed.

The strong high altitude winds that were bringing in pollutants from west Asia and stubble burning regions of Punjab and Haryana have become calm. This would ensure that no external pollutants can enter Delhi at least for the moment.

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