A man is seen walking wearing a mickey mouse costume at Rajpath, which is covered by thick layer of smog. (Photo | PTI)
A man is seen walking wearing a mickey mouse costume at Rajpath, which is covered by thick layer of smog. (Photo | PTI)

Air quality index 'very poor', strong winds on Sunday to bring relief to Delhiites

Transport-level winds coming from the eastern direction expected to prevent pollutants emanating from regions where stubble is burnt

NEW DELHI: Air quality in the national capital improved slightly to settle into the lower end of the 'very poor' zone. As surface winds remain low, pollution levels are likely to remain so at least till November 21, when winds are likely to pick up, weather officials said.

As per the Central Pollution Control Board (CPCB), Delhi's overall air quality index (AQI) was 347, as against 375, the previous day. As per the Union ministry's System for Air Quality and Weather Forecasting and Research (SAFAR), air quality is likely to improve but remain the same for the next two days as transport level winds are coming from the east direction, and preventing intrusion of any pollutants from the stubble burning region.

"Local surface winds are low and mixing layer height is above 1 km resulting in moderate ventilation of near surface pollutants. From November 21, surface winds are likely to be strong, resulting in effective dispersion that may improve air quality," it said.  

Delhi has been experiencing 'severe' to higher end of 'very poor' air quality since November 5 (post-Diwali Day) when the AQI soared to 462. According to the India Meteorological Department (IMD) officials, on Thursday, the wind direction changed to southeasterly from northwesterly.

"Transition in wind direction causes winds to slow down. The moisture-laden southeasterly winds and shallow fog in the morning are likely to further trap pollutants. Owing to these factors, any significant improvement in air quality is likely after November 21," said a senior IMD scientist.

He further said that while northwesterly winds are cold and dry, easterly/southeasterly winds are relatively warmer and humid. "The southeasterly winds are likely to stay till  November 20, when there is cloud cover likely as well, which combined with these winds will allow the night temperature to rise up to 12 degrees Celsius. There might be some dispersion around this time. Northwesterly winds are likely to return to Delhi from November 21-22, with which the mercury will again see a gradual drop and the night temperature may fall to 8 degrees Celsius around that time," he said.

On Thursday, the minimum temperature was 10.5 degrees C, two notches below the  season's average. Delhi on Wednesday recorded the season's lowest minimum temperature so far - 9.6 degrees C, three notches below normal for this time of the year.

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