Air quality enters ‘very poor’ zone by Tuesday eveningUpdated: Dec 04, 2019 22:32 IST
Delhi’s air quality continued to deteriorate on Wednesday with the AQI index value of 296, only five points short of the ‘very poor’ zone, as per the daily average readings released by the Central Pollution Control Board at 4.30pm. However, by evening, the air quality entered the ‘very poor’ with AQI value at 308.
The air quality index (AQI) was recorded at 282 on Tuesday.
Experts said slow wind speed and a dip in the temperature were primarily responsible for holding down pollution particles. The minimum temperature on Wednesday settled at 7.9 degrees Celsius, the lowest of the season. The day’s maximum was recorded at 24 degree Celsius, a notch below the season’s normal.
Scientists at the India Meteorological Department (IMD) said low surface wind speed and a dip in mercury are not likely to allow dispersion of pollutants over the next three to four days. By Friday, the minimum temperature may touch 7 degrees C.
The average wind speed was 8-10 kmph, which is much lesser than 18-20kmph on Tuesday. Also, partly cloudy sky did not allow much sunlight to warm up the earth’s surface.
“At present, we have an anti-cyclonic wind pattern, which slows down the surface winds. During the morning hours, winds are likely to slow down further to 1-2kmph. Besides, a dip in mercury is expected over the next few days,” said Kuldeep Srivastava, IMD’s head of regional weather forecasting centre (RWFC).
At 9pm, the average AQI of the city had already slipped into the ‘very poor’ zone, at 307. Monitoring stations, including Anand Vihar, Wazirpur, Rohini, Jahangirpuri, Nehru Nagar and Alipur recorded AQI above 350.
System of Air Quality and Weather Forecasting and Research (SAFAR), ministry of earth science’s weather and air quality forecasting centre, forecast showed said the AQI is likely to deteriorate to the higher end of ‘very poor category’ on Thursday and predicted that it is also likely to touch ‘severe’ levels in some regions of Delhi on Friday.
SAFAR data showed that the farm fire count was 250 on Tuesday. “Transport-level winds are northwesterly and favourable for stubble plume intrusion. Smoke from stubble burning is likely to account for nine per cent of Delhi pollution PM2.5 (fine particulate matter with diameter less than 2.5 micrometres) pollution on Thursday,” the analysis read.