Clear skies, bright sun, but AQI over 400 in Delhi

Scientists from the India Meteorological Department (IMD) said that the winds remained calm through Tuesday night, but an approaching western disturbance might help improve the situation from December 12.

The sun is out and air quality apparently appears to be good but in fact air quality index in Delhi has been in “severe” category on Wednesday morning.

An IMD scientist said that from December 14, Delhi’s air quality will deteriorate again due to dense fog. (ANI / Twitter)

According to Central Pollution Control Board’s data, the AQI is 403 in Delhi. It was in “very poor” category for the past four days. On December 6, the AQI was “severe” at 404. According to India Meteorological Department, the reason the air quality has deteriorated again is because wind speed fell to almost zero on Tuesday night and Wednesday early morning.

“There was no scope for dispersion because of calm conditions. There was also a change in wind direction from Northwesterly to easterly. There is also some moisture in the air. We are expecting light rain on Thursday night because of a western disturbance,” said Kuldeep Shrivastava, head, regional weather forecasting centre.

Earlier on Monday, the Supreme Court had partially lifted its ban on construction activities in the Delhi-NCR region, allowing them between 6am and 6pm, after the Central Pollution Control Board said that air quality index (AQI) level is not severe at present.

According to IMD’s bulletin on Wednesday, western disturbance as a cyclonic circulation extending upto mid-tropospheric levels lies over Afghanistan and neighbourhood. “Under its influence, an induced cyclonic circulation is likely to form over southwest Rajasthan and adjoining Pakistan during next 24 hours. Fairly widespread to widespread precipitation with heavy rainfall/snow at some places along with thunderstorm, hailstorm and lightning very likely over Western Himalayan region on December 12 and 13.”

The minimum temperature in Delhi and NCR will go up temporarily till December 14 because of clouding associated with western disturbance.

As per air quality early warning models of ministry of earth sciences, while the air quality is likely to remain in very poor category on December 11, it will start improving from afternoon. It will improve significantly on December 12, owing to rain and strong surface winds.