The counsel for the Centre submitted that in reference to the overall air quality status of Delhi (2018-2019), there had been an improvement in air quality in 2019 (from January up to November 2) against 2018. "Correspondingly, the number of 'poor' to 'severe' days declined to 131 against 149 in 2018", said the Centre in its affidavit.
According to the Centre, the bursting of firecrackers during Diwali, stubble burning and adverse meteorology conditions exacerbated the pollution level in Delhi-NCR.
The air quality on the October 30 night, when the air quality index (AQI) reached the severe category, continued to deteriorate up to the November 2 morning.
Explaining the bad air quality, the Centre said it improved till November 2 evening, but high winds around 5 p.m. kicked up local dust, which got suspended in the moist air in north-west of Delhi.
High relative humidity due to light scattered rain led to secondary aerosol formation, causing spurt in particulate matter levels and air quality on November 3 was recorded in the severe+ category, the affidavit aid.
The Centre submitted that the Environment Ministry and the Central Pollution Control Board (CPCB) had been monitoring the air quality trends and also tracking actions to be taken by various government and private agencies.
The hearing will continue on November 6.
(Sumit Saxena can be contacted at sumit.s@,in)
( With inputs from IANS )