Pollutants from farm fires hit season high as Delhi air in red for third day

Delhi’s air stayed in the severe zone for the third consecutive day on Sunday as the average air quality index was recorded at 428, with the share of farm fires to Delhi’s PM2.5 (particulate matter) pollution spiking to the season’s highest so far at 48%.

Scientists said despite an improvement in the wind speed to 8-10km/hr during the day, the high concentration of pollutants from stubble fires in the states of Punjab and Haryana ensured that air quality did not improve. Though the average AQI dropped from Saturday’s 437, the air quality stayed in the severe zone.

The air quality in the capital plunged into the severe category on November 5, a day after Diwali for the first time since January, due to a blatant violation of the ban on bursting of crackers and the increase in the number of farm fires.

According to the System of Air Quality and Weather Forecasting And Research (Safar), a forecasting body under the Centre, strong winds are blowing from the northwest bringing pollutants from the stubble fires to the capital. Despite incidents of farm fires dropping to 4,189 on Sunday from 6,500 on Saturday, Safar said stubble burning contribution was the highest so far this season.

Citing the drop in the AQI on Sunday, Safar said the air will continue to improve and may end up in the higher end of the ‘very poor’ category (AQI value of 300-400), but added that the northwesterly winds will continue to bring emissions from the farm fires.

The Central Pollution Control Board (CPCB) said it will hold a meeting on Monday to review the situation and to consider implementing Graded Response Action Plan (Grap) measures mandated under the severe category. Currently, steps under the very poor category such as ban on diesel generators and three-four times increase in the parking fee are in force in the city.

Prashant Gargava, member secretary, CPCB, and part of the sub-committee on Grap, said air pollution levels are gradually improving, with the IMD’s forecast showing air quality could improve to ‘very poor’ by Monday. However, a meeting of the sub-committee will be held on Monday evening to take stock of the situation. “No additional measures are being introduced at the moment. Another meeting will be held on Monday to see if this declining trend in AQI continues,” he said.

According to the IMD, visibility at the Palam airport on Sunday was recorded between 1200 and 2200 metresthroughout the day, while wind speed was around 10 km/hr during the day. “Day-time winds continued to be around 8-10 km/hr. Visibility improved on Sunday, but by the evening, this wind speed had again dropped to ‘light’ or ‘calm,” said R.K Jenamani, scientist at IMD. Forecasts by the Early Warning System (EWS), developed for Delhi, showed wind speed is expected to be between 4 and 16 km/hr on Monday.

Anumita Roy Chowdhury, executive director, research and advocacy at the Centre for Science and Environment (CSE) said with three consecutive severe days, this can now be classified as an episodic smog event and stricter measures under Grap may now be required. “In the past, we have seen up to seven consecutive severe air days and even then, only strong winds, or rain came to the rescue for Delhi. Until then, we may need more restrictions in place,” she said.