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Delhi’s air slowly inches towards ‘severe’

PUBLISHED ON DEC 26, 2019 11:04 PM IST

New Delhi

Air quality in the national capital continued to remain in the ‘very poor’ zone on Thursday, as winds slowed down and a moderate fog layer did not allow pollutants to disperse. The air quality is likely to plunge to ‘severe’ on December 28-29 after the wind speed slows down and as there is an increase in dense fog, government agencies warned.

The overall air quality index (AQI) on Thursday, as recorded by the Central Pollution Control Board (CPCB)’s 4pm bulletin, was 349 in the ‘very poor’ zone, as against 350, the previous day.

Scientists at the India Meteorological Department (IMD) said the average wind speed was 8-10kmph, which is not favourable for dispersion of pollutants. Any improvement in the air quality could be expected around December 31 when an approaching Western Disturbance brings rain and hailstorm in Delhi and neighbouring regions.

“The winds are expected to remain slow over the next three to four days, as there is no system forming close to Delhi. Besides, moderate to dense fog is expected over the next three days, which also allows trapping of pollutants, which may push up pollution levels,” said Kuldeep Srivastava, head, IMD’s regional weather forecasting centre.

He added that the whole northwestern region is expected to witness rainfall and hailstorm on the first day of the New Year. “The Western Disturbance will start impacting Delhi’s weather from December 30. On December 31, there could be light rainfall, which will be followed by more rain and hail on the first day of 2020, which is expected to wash away pollutants and improve air quality significantly,” he said.

The System of Air Quality and Weather Forecasting and Research (SAFAR), ministry of earth science’s weather and air quality monitoring centre, forecast also said that on Friday, the AQI is likely to reach the higher end of the ‘very poor’ category and will enter the ‘severe’ category over the weekend.

“Calm surface winds, low mixing layer and dense fog with high humidity are conditions highly favourable for the formation of secondary particulate (more potent and harmful than particulate matter), which could push up pollution levels even higher on December 28-29,” said a senior SAFAR scientist.

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