New Delhi, Sep 27 (PTI) Delhi's air quality improved marginally on Sunday due to high wind speed, while favourable ventilation conditions are likely to keep it in the 'moderate' category for the next three days, a government forecasting agency said.
Sporadic farm fires were observed on Saturday around Punjab and border regions but its impact has been negligible so far due to unfavourable wind direction and speed, the System of Air Quality and Weather Forecasting and Research (SAFAR) said.
The city recorded a 24-hour average air quality index (AQI) of 117 on Sunday. It was 165 on Saturday.
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'.
'AQI has improved marginally due to high wind speed and rainfall in Rajasthan which washed out dust en route to the city, reducing dust intrusion,' the Ministry of Earth Science's air quality monitor said.
'High surface wind speed is predicted... Favourable ventilation condition is likely to keep Delhi's AQI in the moderate category for the next three days,' SAFAR said.
However, it said, the late withdrawal of monsoon and associated stagnant winds are likely to influence Delhi's air quality negatively by the weekend.
The monsoon will start receding from Delhi on Monday, according to the India Meteorological Department. PTI GVS TDS TDS