New Delhi, Nov 7 (PTI) Delhi's air quality remained in 'severe' category on Sunday because of the large influx of stubble-related pollutants, apparently from much higher effective fire count, authorities said.
According to the Central Pollution Control Board (CPCB) data, the city's air quality index (AQI) stood at 416 (severe) at 8 pm.
Chief Minister Arvind Kejriwal also tweeted about the air pollution situation and shared data.
"Nov 7 - AQI - 428 (401 to 500 - Severe) PM10 - 450 (Above 430 - Severe) PM2.5 - 309 (Above 250 - Severe)," he tweeted.
Strong surface winds had slightly improved Delhi's air quality on Saturday but it had remained in the 'severe' category as the contribution of farm fires in the city's PM2.5 pollution had reached the season's highest of 41 per cent.
The AQI on Friday was recorded at 462.
The stubble fire-related contribution simulated by the SAFAR model has risen to the highest level of 48 per cent of this season with SAFAR effective fire count touching nearly 4,189, according to the summary issued by authorities on Sunday.
The CPCB data showed that the AQI on Sunday at Anand Vihar was 424 ('severe' category), Okhla Phase-II 425 ('severe'), R K Puram in 'poor' category, and Rohini registered 446 ('severe').
An AQI between zero 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'.
AQI is expected to improve by November 7 evening according to SAFAR model, officials said.
"Currently, AQI is still in the 'severe' category because of the large influx of stubble-related pollutants which appears to be due to much higher effective fire count observed than that assumed in the SAFAR model for forecasting," the summary said.
In view of this, AQI is likely to improve by tonight to 'very poor' category but continue to fluctuate between the lower end of 'severe' to upper end of very poor. The favourable wind speed and direction and significantly high fire counts since yesterday, the AQI recovery is extremely slow in spite of moderate wind speed, it said.
AQI is forecast to improve but stay in high end of very poor to severe category in the next two days, authorities said.
On Sunday, Delhi's maximum temperature settled at 25 degrees Celsius, India Meteorological Department (IMD) said.
