Even as pollution rises, Gurugram least polluted city in NCR

Air quality experts attributed the deterioration of Gurugram’s air quality to low surface winds.

Even as Gurugram’s air quality continued to deteriorate on Wednesday, measuring 287 (poor)— 47 points lowers than Tuesday’s—on the Central Pollution Control Board’s (CPCB) monitor at Vikas Sadan in Sector 11, Gurugram remained the least-polluted city in the national capital region (NCR). This, however, is not expected to last for long as air pollution is expected to rise and enter the ‘very poor’ category on Thursday, and further deteriorate in the fourth week of October.

On Wednesday, Ghaziabad was the most-polluted city with an air quality index (AQI) of 339 (very poor), followed by Noida at 326. Delhi recorded an AQI of 304, as per the data shared by the CPCB.

Particulate matter (PM) 2.5 was the primary pollutant in Gurugram’s air and was at its peak at 1am with a reading of 133ug/m3, as per the CPCB data. According to the national standard, PM2.5 level above 60ug/m3 is considered hazardous.

Air quality experts attributed the deterioration of air quality to low surface winds. “The changing weather conditions and low wind speed isn’t letting the particulate matter disperse. The temperature has also started to cool and the pollutants get settled at a lower height in the atmosphere,” independent air quality expert Sachin Panwar said.

Wednesday’s wind speed, as recorded at 5pm by the India Meteorological Department’s station in Palam, was 7 kilometres per hour (kmph).

No improvement in sight

As per the CPCB forecast, the AQI is likely to fall further to the lower end of the ‘very poor’ category on Thursday, and is expected to further deteriorate in the fourth week of October. “Stagnant weather conditions, such as low wind speed and descending air, will favour accumulation of pollutants. If encountered with additional internal (firecrackers) or external (stubble burning) emissions, the crisis would deepen,” the forecast stated.

According to the CPCB, the maximum ventilation index is likely to be 4,500 m2/s on Thursday. A ventilation index lower than 6,000 m2/s with an average wind speed below 10 kmph is unfavourable for dispersal of pollutants. The wind speed, according to the IMD, is likely to be around 8 kmph.