Delhi's air quality improves from 'severe' to 'very poor'

Chandigarh: Air quality improved in Delhi from 'severe' to 'very poor' on Tuesday as the wind flushed out pollutants but it is likely to deteriorate by Thursday as the number of fires in fields of Punjab and Haryana have increased substantially and weather conditions are likely to blow the fumes towards the Capital.

Satellite images show that the number of farm fires has increased to 2,577 from 1,654 in the past 24 hours, the pollution monitoring and forecasting unit of the Indian Institute of Tropical Meteorology, Safar, said in its latest report. Burning of harvest residue is expected to continue for two weeks, which means many parts of the north will remain vulnerable to a sharp deterioration in air quality depending on meteorological conditions such as humidity, temperature and wind flow pattern.

Presence of clouds and a hazy morning, prompted many in the capital to believe that Delhi was shrouded with smog, but weather scientists said the level of the tiny PM 2.5 particles had actually fallen. “Boundary layer winds speed of last night. As of today (Tuesday), the stubble plume from north-west regions has become one of the significant factors in deteriorating Delhi's air quality,” the Safar report said. The share of farm fumes in Delhi is forecast to rise to this year’s peak of 29% on Wednesday, improving slightly the next day.

“Increase in boundary layer wind speed is expected by November 1, likely to bring improvement in AQI,” the report said. So far, burning of crop residue has risen 18% in Punjab, while there is a small improvement in Haryana. Air quality after Diwali was better than last year in Delhi and neighbouring Gurgaon and Faridabad, but was worse in some districts of Haryana including Rohtak and Panchkula.