Winds help city breathe a little easy on Tuesday
Agencies, however, say air quality may deteriorate on Wed morning
NEW DELHI: Clear skies, a bright sun and strong surface winds on Tuesday helped the air quality improve to the ‘very poor’ zone after reeling in ‘severe’ conditions for the past two days.
The hourly particulate matter (PM) concentration too came down remarkably on Tuesday afternoon, after remaining in the ‘emergency’ zone the previous day.
Pollution monitoring agencies said air quality is likely to deteriorate again for a while on Wednesday morning but will recover by evening. This is mainly on account of reduced wind speed and cloud formation, increasing the moisture content in the air, which traps pollutants.
The 24-hour-average air quality index (AQI) as calculated by the Central Pollution Control Board (CPCB) at 4 pm on Tuesday was 324. This was against 407 the previous day and a marked improvement from Sunday, the worst air day recorded since 2016 with an AQI reading of 495.
The real-time average concentration of PM 2.5 levels – the most harmful aerosols -- came down to the safe limits to 58 ug/m3 by 3 pm on Tuesday after being in the ‘emergency’ zone at 380ug/m3 at 3 am, data released by the Delhi Pollution Control Committee (DPCC) said.
According to Indian standards, the safe limits of PM 2.5 is 60ug/m3. If the levels reach 300ug/m, it is considered to be in the ‘emergency’ zone.
As per CPCB data, on Monday at 6 pm, the 24-hour average PM 2.5 concentration was 195 ug/m3. On Monday, around the same time, the level was above the emergency mark of 300ug/m3 and started falling after 7 pm. The level was nine times above the safe limit at 550ug/m3 on Sunday when Delhi was enveloped in a blanket of smog.
“It was a bright, sunny and windy day, which helped in dispersion of pollutants. As per inputs from the India Meteorological department, air quality may dip again on Wednesday because of formation of clouds resulting from a Western Disturbance, but the magnitude will not be very high and pollutants will dissipate by evening. It is likely to remain in ‘very poor’ zone,” said a senior CPCB official.