Residents of the national capital saw a striking improvement in air quality on Tuesday, as the Air Quality Index (AQI) plummeted to 268 (poor). But the relief may not last long as the toxic smog is projected to deteriorate to severe levels around Diwali due to additional emissions from firecrackers and stubble/waste fires.The latest forecast from IITM, Pune, shows the AQI fell from 304 (very poor) on Monday to 268 (poor) the next day, but it is likely to cross the severe mark of ‘400’ on October 31 and November 1. The winds are weak – blowing at 4-8 kmph, dropping dramatically at night. The day temperatures are settling around 34-35℃, and have not fallen as much, as expected at this time of the year.“When the weather cools, the inversion layer of the atmosphere (upper lid of atmosphere) descends. It also reduces the ventilation co-efficient – the rate at which the pollutants disperse. So if that happens, then it can be disastrous for Delhi,” said Prof Gufran Beig, former founder-director of SAFAR (System of Air Quality and Weather Forecasting and Research) in an exclusive interview.Latest weather predictions indicate a fall of 2-3℃ after November 2, and calm winds. “If the bursting of firecrackers continues as it did last year, then Delhi residents can face a very tough situation from the midnight of November 1, as it could temporarily spike the pollutant levels,” he added.SIGNIFICANT DROP IN STUBBLE FIRES THIS YEAR TOOTo everyone’s relief, there have been lesser instances of stubble burning since 2021, and this year has been no exception. The overall fire count has decreased by half in Punjab which has the largest area under paddy cultivation. Only 2,356 fire counts were reported from September 15 in Punjab, compared to 5,254 last Kharif season. It is lesser in Rajasthan and Madhya Pradesh as well, but the improvement in Uttar Pradesh is not as much.“Roughly 300 to 400 fire counts are being reported daily. Earlier, it used to be much more. But the peak days are yet to come, which is generally the first two weeks of November. So, if that happens, and the winds become north-westerly, then together it can dump high amounts of PM2.5 concentrations into the air,” said Prof Beig, who is now working at the National Institute of Advanced Studies (NIAS), Bengaluru.CAN DELHI’S AIR EVER BE CLEAN?According to experts, Delhi’s perennial pollution problem needs to be addressed through an air-shed approach under which similar mitigation measures must be put into place in adjoining states as well. Even though road-dust remains a culprit for high PM10 concentrations in Delhi, experts point out that the focus should be on controlling the most toxic PM2.5 which is produced from combustion of fossil fuels – coal, gas and oil.“Fossil fuel emissions, mainly the transport sector, are responsible for the majority of the most PM2.5 concentrations in Delhi, and it is far more dangerous than PM10. Therefore, we must focus on reducing the congestion on roads. Also, we have worked enough on a city-level emission approach, now the need is to implement actions in adjoining states as well. Unless that happens, we will not see any significant change in air quality,” he added.
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