A day after Delhi’s air quality was pushed into the ‘severe’ zone due to fireworks on the day of Diwali, the volume of pollutants considerably slipped on Saturday due to a strong wind movement throughout the day.
According to the Central Pollution Control Board (CPCB), the situation will improve further by Sunday, if favourable conditions prevail. “The wind speed is expected to pick up and reach up to 9 km/hour, which is adequate enough for the dispersion of suspended particulates. Yesterday and the day before, the wind speed and mixing height were extremely low, which led to the rapid build-up of pollutants near the surface,” CPCB officials said.
The improvement was captured by the pollution monitoring stations. Six of the eight stations maintained by SAFAR (System of Air Quality Forecasting and Research), an agency under the Ministry of Earth Sciences, had air quality index (AQI) in the ‘very poor’ category, a shade better than “severe”. Among the stations maintained by the CPCB, nine of the 17 were in the “very poor” category, while the rest recorded “severe” air quality.
At 12 pm, the 24-hour rolling average of PM2.5 and PM10, ultra-fine particulates, which are up to 30 times tinier than the width of a human hair, were 206 and 357 microgrammes per cubic metre (ug/m3) respectively, as against yesterday’s 407 and 595.
The Supreme Court’s ban on the sale of firecrackers in the National Capital Region (NCR) to lessen the health risks this year had some impact as Delhi had its cleanest Diwali in three years, but pollution levels still peaked to dangerous levels on Thursday night and Friday morning.
ON RECORD
- The CPCB had on Friday recorded an air quality index (AQI) of 403 in Delhi, 402 in Noida and 412 in Ghaziabad, all in the severe zone, or the most polluted category, on October 20.
- The sulphur dioxide levels that otherwise remain very low in the region, had increased by more than three times in several locations
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