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’.
High surface wind speed and favourable ventilation condition is likely to keep Delhi’s AQI in the moderate category on Thursday, the System of Air Quality and Weather Forecasting and Research (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 second week of October.
By October 2, the air quality is likely to slip to the “lower end of the poor category”, it said.
The monsoon withdrew from most parts of northwest India, including Delhi-NCR, on Wednesday, according to the India Meteorological Department. SAFAR said it observed an increase in farm fires in Punjab, Haryana and neighbouring border regions, but only a marginal impact is expected in Delhi for next two days.