NEW DELHI: After a day of slight improvement, air quality in the national capital oscillated between ‘severe’ and ‘very poor’ on Saturday.
According to the Central Pollution Control Board, the overall Air Quality Index (AQI) reached 407 in ‘severe’ category, at 4 PM, and improved to 400 by 6 PM, in the ‘very poor’ category. Sixteen areas recorded ‘severe’ air quality, while 17 had ‘very poor’ air.
An AQI between 100 and 200 comes under ‘moderate’ category, 201 and 300 is considered ‘poor’, 301 and 400 ‘very poor’, while that between 401 and 500 is ‘severe’.
The concentration of harmful pollutants PM2.5 (Particulate Matter) and PM10 in the ambient air was recorded at 220 microgramme per cubic metre (ug/m3), and 357 ug/m3, according to System of Air Quality and Weather Forecasting and Research (SAFAR).
It said air quality is likely to improve owing to forecast of rainfall and good wind speed, which will help in dispersion of pollutants that have accumulated in the ambient air. “An active Western disturbance is very likely to cause fairly widespread moisture intrusion over northern region, including Delhi. Rapid improvement is expected only if sufficient amount of rainfall occurs whose probability is less,” the SAFAR said.
“Little showers with calm winds only aggravate the situation rapidly,” it said. Fog intensity is likely to decline with increased gusty winds. “An active Western disturbance is likely to cause fairly widespread moisture intrusion over the northern region, including Delhi, but only after three days when withdrawal is expected.”