Delhi's air pollution level moved from 'severe' to 'very poor' on Saturday. The 24-hour average air quality index (AQI) stood at 381, a considerable improvement over the AQI of 447 a day ago, according to the Central Pollution Control Board. The improvement in air quality can be attributed to favourable wind speed and a dip in stubble burning. AQI had jumped to 450 on Thursday, just a notch short of the 'severe plus' category, prompting the authorities to invoke the final stage of anti-pollution curbs, including a ban on non-BSVI diesel light motor vehicles.


"The wind direction will change frequently over the next few days due to back-to-back western disturbances. Hence, the net result will be very poor air quality," Mahesh Palawat, vice president of meteorology and climate change at Skymet Weather told PTI.


The air quality is likely to slip back into the "severe" category on Sunday morning due to shallow fog and improve thereafter.


Stubble Burning 


According to Safar, a forecasting agency under the Ministry of Earth and Sciences, the share of stubble burning in Delhi's PM2.5 pollution dropped to 21 per cent on Saturday from 30 per cent on Friday due to unfavourable transport-level winds. Transport-level winds blow in the lowest two layers of the atmosphere --troposphere and stratosphere -- and carry smoke from farm fires to the National Capital Region.


Chief Minister Arvind Kejriwal and his Punjab counterpart, Bhagwant Mann, owned responsibility for the polluted air in Delhi and for paddy straw burning in the agrarian state on Friday. The AAP's Chief Ministerial duo also promised to curb the stubble-burning practice by next winter.


The number of stubble-burning incidents in Punjab rose by 12.59 per cent year-on-year to 26,583 in the last 50 days with a spurt in such cases after Diwali, according to the Indian Council of Agricultural Research.


Curbs To Control Pollution Levels


The hazardous pollution levels prompted the Delhi government to announce on Friday that primary schools would remain shut from Saturday and 50 per cent of its staff will work from home, while private offices have been advised to follow suit.


A six-member panel chaired by the special commissioner of transport has been set up to monitor the implementation of curbs on anti-polluting activities. Revenue commissioners have been asked to prepare a plan for staggered timings of markets and offices.


Kejriwal had said the odd-even car rationing scheme would be implemented if the need arises and discussions on it were on.