NEW DELHI: Despite a slew of restrictions in Delhi-NCR from mid-November, air quality in the city has more or less been in the ‘very poor’ zone, as per government data. Weather experts said that unlike past years, this season, the pollutants accumulated since Diwali have not been dispersed completely. This is mainly because the city did not receive strong western disturbances that would have wiped the pollutants away.
On Wednesday, December 15, 2021, Delhi recorded the third straight day of ‘very poor’ air quality with an air quality index (AQI) reading of 363. There was a minor improvement with winds picking up on December 11 and 12, when it had improved to ‘poor’ category, the Central Pollution Control Board data showed.
The period between November 15 and December 15 this year has recorded only five poor days, while the rest of the days remained in the ‘very poor’ to ‘severe’ categories. November recorded 11 ‘severe’ days, the highest in six years.
The consistently bad pollution days prompted the Supreme Court to step in. Following which, the Commission for Air Quality Management (CAQM) in Delhi-NCR and adjoining states on November 16 issued a slew of directions including shutting down of schools, colleges and other educational institutions, banning the entry of trucks in Delhi, ban on industries not using clean fuel and thermal power plants in the NCR districts.
V K Soni, senior IMD scientist, said that this November, the city did not receive a good spell of rain, as none of the western disturbances were strong enough.
“In the Indo-Gangetic plains, weather becomes difficult during the winter season; as winds remain calm, not allowing enough dispersion. But, with some strong western disturbances, the accumulation built up initially after Diwali or during the peak stubble burning season is cleansed. Since this did not happen this, the pollutants concentrated in the atmosphere remained there largely, with a little dispersion intermittently and hence no moderate air quality days were reported,” said Soni.
Vice-president of Skymet Mahesh Palawat said the post-Diwali accumulation was not cleaned up entirely, which is why the AQI is still in ‘very poor’ zone. “This year, there was no strong system building up in the Bay of Bengal or the Arabian Sea to induce a western disturbance, strong enough to have an impact on pollution in the city,” said Palwat.
