The share of pollutants from farm fires in Delhi’s air increased to around 32% Saturday, the second highest figure for the season, causing the air quality to remain in the very poor category despite improved weather conditions.
As per the Centre’s System of Air Quality and Weather Forecasting and Research, stubble burning-related fire counts in neighbouring Punjab, Haryana and UP were around 3,400 on Friday, the season’s highest so far. An improvement in Delhi’s air quality index (AQI) was expected Saturday morning with increase in wind speed, but it could not happen due to higher intrusion of stubble burning emissions, the SAFAR bulletin said. “Increased local surface wind speed with faster dispersion conditions are counteracting with increased fire-related emission… But still, AQI is likely to improve for the next two days as dispersion will eventually play a lead role,” the bulletin said.
Delhi’s 24-hour average AQI on Saturday was 367 (very poor), lower than 374 recorded Friday, as per the Central Pollution Control Board. As per SAFAR data, contribution of stubble burning to Delhi’s PM 2.5 levels reached 36% on October 29, the highest since count began on October 10.
CPCB data shows the hourly average concentration of PM 2.5 in Delhi-NCR has been above 200 µg/m3 October 29 onwards, against its 24-hour acceptable limit of 60 µg/m3. As of 5 pm on Saturday, its concentration was 235 µg/m3. The hourly level of PM 10 in Delhi-NCR has been above 350 µg/m3 October 29 onwards against its 24-hour acceptable limit of 100 µg/m3. At 5 pm on Saturday, its concentration was 409 µg/m3.
The predominant wind direction until Monday over Delhi-NCR is forecast to be from the northwest, favourable for transporting stubble burning pollutants, as per the Ministry of Earth Sciences’ Air Quality Early Warning System (EWS) for Delhi. EWS has forecast that AQI in Delhi-NCR will remain ‘very poor’ until Monday.
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