Gurgaon: City’s air quality index (AQI) stood at 156 on Monday, remaining in the moderate category. The AQI was 134 on Sunday, indicating a jump of 22 points in a day. The city’s AQI had been 215 on Friday and 193 on Thursday, after rising to 216 on Wednesday. It was 184 on Tuesday and 132 on Monday, Oct 19. The AQI calendar listed particulate matter (PM10) as the dominant pollutant on several days, while PM2.5 was recorded on others.Among the four active air quality monitoring stations in the city, TERI Gram recorded the highest reading at 180, followed by NISE Gwalpahari at 152, Vikas Sadan at 149 and Sector 51 at 135, according to Central Pollution Control Board (CPCB). The readings showed variations across monitoring locations.Officials said the marginal dip in AQI was likely due to changes in local dispersion conditions, but warned that the improvement — as compared to last week — was limited and uneven across neighbourhoods. “There was deterioration in dispersion as a result the pollutants are lingering as there is drop in the temperature and wind speed remain low,” an official from Haryana State Pollution Control Board (HSPCB) said.The Air Quality Early Warning System for Delhi, under the Union ministry of earth sciences, has forecast a decline in the ventilation index over Delhi from 11,000 m²/s on Oct 26 to 6,000 m²/s on Oct 27 and 3,800 m²/s on Oct 28. A ventilation index below 6,000 m²/s, coupled with an average wind speed of less than 10 kmph, is unfavourable for pollutant dispersion. The maximum mixing depth is also forecast to decline from 2,200 metres on Oct 26 to 1,500 metres on Oct 27 and 1,300 metres on Oct 28.CPCB guidelines classify AQI between 201 and 300 as ‘poor’, a level at which most people may experience breathing discomfort on prolonged exposure. AQI between 301 and 400 is categorised as ‘very poor’, where the likelihood and intensity of health impacts increase further, particularly for sensitive groups.
