Farm fires contributed 23% in Delhi pollution on Tuesday, max so far: SAFAR

The share of stubble burning in Delhi's PM2.5 pollution rose to 23 per cent on Tuesday, the maximum so far this season, according to a central government air quality monitoring agency.

It was 16 per cent on Monday, 19 per cent on Sunday and nine per cent on Saturday.

The number of farm fires in neighbouring states was 1,943 on Monday, the highest so far this season, according to the Ministry of Earth Sciences' air quality monitor, SAFAR.

"Stubble burning share in Delhi PM2.5 concentration was 23 per cent on Tuesday due to favourable transport-level wind direction and speed, it said.

However, Delhi's air quality improved marginally due to an increase in surface wind speed, SAFAR said.

According to the India Meteorological Department, the predominant wind direction was westerly-northwesterly and the maximum wind speed was 15 kilometres per hour. The minimum temperature was recorded at 14.4 degrees Celsius.

Calm winds and low temperatures trap pollutants close to the ground, while favourable wind speed helps in their dispersion.

The air quality index (AQI) is likely to improve slightly on Wednesday but pollution levels will rise again on Thursday, SAFAR said.

The city recorded a 24-hour average AQIof 312 on Tuesday. It was 353 on Monday, 349 on Sunday, 345 on Saturday and 366 on Friday.

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'.