New Delhi | Jagran News Desk: Delhi's air quality continued to be in the ‘poor’ category on Sunday morning. The national capital's air quality index was recorded 276 at 7 am, according to government data. Notably, it's a marginal improvement from yesterday's AQI which was stood at 289.  

According to a central government agency, the share of stubble burning in Delhi's PM2.5 pollution is likely to “increase significantly”. It was 19 percent on Saturday, 18 percent on Friday, around one per cent on Wednesday and around 3 per cent on Tuesday, Monday and Sunday. 

The city recorded an air quality index (AQI) of 275 at 8:30 am. The 24-hour average AQI was 287 on Saturday. It was 239 on Friday and 315 on Thursday, the worst since February 12 (AQI 320). 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'.

During daytime, winds are blowing from northwest, bringing pollutants from farm fires. At night, calm winds and low temperatures are allowing accumulation of pollutants, according to an India Meteorological Department official.

The Ministry of Earth Sciences'' air quality monitor, SAFAR, said the farm fire count around Haryana, Punjab and its nearby regions across the International Border on Saturday was 882.

"Since transport-level wind direction is favourable for intrusion, stubble contribution in PM2.5 is around 19 per cent on Saturday," it said.

The Ministry of Earth Sciences'' Air Quality Early Warning System for Delhi said the ventilation index -- a product of mixing depth and average wind speed -- was 10,000 metre square per second on Saturday -- favourable for dispersion of pollutants.

Mixing depth is the vertical height in which pollutants are suspended in the air. It reduces on cold days with calm wind speed. A ventilation index lower than 6,000 sqm/second, with average wind speed less than 10 kmph, is unfavourable for dispersal of pollutants.

The impact of stubble burning on the national capital''s air quality is likely to "increase significantly" by Monday, the Ministry of Earth Sciences'' Air Quality Early Warning System for Delhi said.

Punjab and Haryana have recorded more incidents of stubble burning this season so far compared to last year, largely due to early harvesting of paddy and unavailability of farm labour due to the coronavirus pandemic, officials said on Saturday.

(with PTI inputs)

Posted By: Rakesh Kumar Jha