New Delhi: Delhi's air quality improved marginally on Monday as wind speed picked up dispersing the pollutants and the thick cover of hazardous haze that shrouded the city for nearly a week.
However, monitoring agency SAFAR had 24-hour-average (rolling) level of respirable pollutants PM 2.5 and PM 10 in the 'severe' category at 622 and 808 micrograms per cubic metre respectively at 5 PM.
The alarming levels of pollution failed to dissuade Chhat revellers though from bursting firecrackers early in the morning.
The 24-hour-average Air Quality Index (AQI) recorded by Central Pollution Control Board (CPCB) was 423 as against yesterday's 497 which was the season's worst.
The visibility also improved as the city witnessed sunshine after several days.
"The air quality has improved due to a little increase in wind speed, although the wind direction continues to be north-northwest. By Wednesday wind speed is likely to increase more and wind direction will also be easterly which is likely to further improve the air quality and turn it very poor from severe," Project Director of SAFAR Gufran Beig told PTI.
The wind direction is important from the point of view of stubble burning in Punjab and Haryana which falls in the northest region. Wind blowing from that direction brings pollutant-laden smoke to Delhi.
The Delhi Pollution Control Committee's (DPCC) real-time readings displayed a downward trend cutting across its monitoring stations.
The city's pollution hotspot Anand Vihar had a PM 10 reading of 1640 micrograms per cubic metre at 4 AM. It came down to 580 by 5 PM while PM 2.5 was at 145 micrograms per cubic metre.
At Punjabi Bagh, PM 10 came down to 214 micrograms per cubic metre at 5 PM from a high of 1270 recorded at 10 AM.
Other stations like Mandir Marg and RK Puram displayed similar trends. PM 2.5 and PM 10 are ultrafine particulates, the dominant pollutants in Delhi, which has recently been described as a "gas chamber" by Chief Minister Arvind Kejriwal.
The 24-hour prescribed standards of PM 2.5 and PM 10 are 60 and 100 respectively and prolonged exposure to anything beyond that harms the respiratory system and may cause cardiac complications.