Delhi air pollution: AQI may stay in very poor zone till Nov 1, says forecast

New Delhi: Delhi’s air quality index (AQI) improved slightly on Sunday, yet remained in the higher end of the ‘very poor’ category with a reading of 352, according to the Central Pollution Control Board’s 4pm daily bulletin

New Delhi: Delhi’s air quality index (AQI) improved slightly on Sunday, yet remained in the higher end of the ‘very poor’ category with a reading of 352, according to the Central Pollution Control Board’s 4pm daily bulletin.

Commuters in Anand Vihar walk through a dense blanket of smog in the early hours of Sunday amid deteriorating air quality levels, in New Delhi, on Sunday. (Sanjeev Verma/HT Photo)

On Saturday, Delhi’s AQI had briefly touched the ‘severe’ category, before settling at an average of 397 (very poor). Forecasts show that with the contribution of stubble fires to pollution in the city on the rise, and calm wind conditions expected over the next three days, Delhi’s AQI is expected to hover between ‘very poor’ and ‘severe’ till November 1.

“While meteorological conditions have largely remained the same in the last 24 hours, we have seen a slight dip (in AQI) in the aftermath of the control measures that have been put into place from Saturday evening onwards as part of the Stage-III of the Graded Response Action Plan (Grap). Winds are becoming calm in the evening and remain so until the early hours of the next day. This is trapping pollutants locally. At the same time, we are seeing a rise in the number of farm fire cases,” said VK Soni, scientist at India Meteorological Department (IMD) and part of the Commission for Air Quality Management (CAQM) sub-committee on Grap.

Meteorologists said that two western disturbances are likely to hit Western Himalayan region between November 3 and 6, but they may bring only temporary relief. “The first western disturbance approaching on November 1 will be weak and the second western disturbance which will impact on November 4, 5 and 6 may induce light rain over Punjab, Haryana, Delhi-NCR etc. But, it’s very difficult to say if patchy rains will clear up pollution,” said Mahesh Palawat, vice president, climate and meteorology at Skymet Weather.

CAQM had introduced Stage-III of Grap on Saturday evening with immediate effect, owing to forecasts which showed severe air in the coming days. The measures include a ban on construction and demolition (C&D) activities across NCR, shutting down of brick kilns and hot mix plants not operating on clean fuels and shutting down of all stone crushers across NCR. It also includes a ban on mining across NCR.

The forecast by Early Warning System (EWS) for Delhi, on which CAQM relies to take pre-emptive action, shows the AQI will be between ‘very poor’ and ‘severe’ on Monday and Tuesday. “The air quality is likely to improve to the ‘very poor’ category on Wednesday. The outlook for subsequent six days shows AQI largely remaining in the ‘severe’ to ‘very poor’ range,” said EWS.

In addition to calm winds, intrusion of additional emissions through stubble burning is one of the other key factors behind Delhi’s deteriorating AQI. As per the System of Air Quality of Weather Forecasting And Research (Safar), the contribution of stubble burning in Delhi’s overall PM 2.5 concentration was 26% on Sunday, 21% on Saturday and 7% on Friday.

“This is expected to remain similar or rise further in the next two days, as strong transport-level winds are bringing these pollutants to Delhi from the north-west direction. The contribution will only dip on November 2, as wind direction changes slightly,” said Gufran Beig, founder project director, Safar.

Delhi meanwhile recorded a maximum temperature of 30.8 degrees Celsius, which is around normal for this time of the season. The minimum was recorded at 15.0 degrees – one degree below normal. Forecast for the next three days, shows the maximum is expected to hover between 31 and 32 degrees, while the minimum will oscillated between 15 and 16 degrees.