Delhi

City’s air quality deteriorates to ‘very poor’ category, says CPCB

The air in the Capital deteriorated on Thursday with the average AQI rising to 395, which is in the upper end of the “very poor” category, said Central Pollution Control Board (CPCB).

This was a day after the AQI improved on Wednesday to the “poor” category.

The AQI at Noida, Gurugram and Ghaziabad were 383, 384 and 389 respectively — all of which are in the “very poor” category. Greater Noida with an AQI of 412 was in the “severe” category.

‘Air likely to improve’

Delhi’s air is likely to improve but remain in “very poor” category on October 30 and is likely to improve further and reach the lower end of “very poor” category on October 31.

An AQI between 0 and 50 is considered “good”, 51 and 100 “satisfactory”, 101 and 200 “moderate”, 201 and 300 “poor”, 301 and 400 “very poor”, and 401 and 500 “severe”.

“Extremely calm surface and boundary layer winds along with the low nighttime boundary layer height resulted in low ventilation, practically stagnant no dispersion condition has resulted in the current situation,” said government-run monitoring agency System of Air Quality and Weather Forecasting and Research (SAFAR).

“The stubble burning share in PM2.5 is estimated as 36% for Thursday. In summary, the stagnant wind-related non-dispersion of locally generated pollution combined with the increased magnitude of external intrusion to be major factors for the increase in the level of PM2.5 for the next 24 hrs. Increased surface wind speed and better ventilation conditions are likely to significantly improve the situation by October 31,” said SAFAR.

“The predominant surface wind is likely to be from North-East direction of Delhi with wind speed upto 10-15 kmph, mainly clear sky and mist in the morning on October 30. The predominant surface wind is likely to be coming North-West direction of Delhi with wind speed upto 08-15 kmph, mainly clear sky and mist in the morning on October 31,” the forecast read.

The Capital also recorded its lowest minimum temperature for October in 26 years with the night temperature on Thursday falling to 12.5 degrees Celsius, which was three degrees colder that the normal for this time of the year, said Met officials.

The city recorded the all-time lowest temperature 9.4 degrees Celsius on October 31 in 1937, according to data available with the Met department.

Last year, the lowest minimum in October was 16.5 degrees Celsius. The minimum temperature is likely to fall to 11 degrees Celsius on October 31.

The maximum temperature on Thursday was 32.2 degrees Celsius which was one degree above normal. The maximum temperature is likely to stay around the 30 degrees mark for the next few days.

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Printable version | Nov 28, 2020 8:26:45 PM | https://www.thehindu.com/news/cities/Delhi/citys-air-quality-deteriorates-to-very-poor-category-says-cpcb/article32976978.ece

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