Delhi's air quality improves; stubble burning contributed the least to city pollution on Wed

Delhi's air quality "improved significantly" on Wednesday as overnight rains washed away bigger pollutants and stubble burning in neighbouring states declined, contributing just three per cent - the lowest this month- to pollution.

Though the conditions provided some respite to the city which has been reeling under "severe" pollution for the past one week, the air quality was still far from safe and fell in the 'very poor' category with AQI of 306.

The AQI has been oscillating between severe and the upper range of very poor for the past one week even crossing 600 post-Diwali.

According to Centre-run System of Air Quality and Weather Forecasting (SAFAR), the contribution of stubble burning to the pollution in Delhi has been recorded the least on Wednesday for this month at 3 per cent. On November 5, the contribution of stubble burning was the highest this month at 33 per cent.

On Wednesday, the PM2.5 -- particles in the air with a diameter of less than 2.5 micrometres -- level was recorded at 175, while the PM10 -- particles in the air with a diameter of less than 10 micrometres -- was recorded at 280 in Delhi, according to the data by the Central Pollution Control Board.

Twenty one areas in Delhi recorded 'very poor' air quality while 14 areas showed 'poor' air quality, the CPCB said.

Similar conditions are likely to prevail in the coming days, according to SAFAR.

Ghaziabad, Faridabad, Greater Noida and Noida recorded 'very poor' air quality while Gurgaon's air quality was recorded in the 'poor' category, it said.

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'.

SAFAR said air quality has "improved significantly mainly due to sufficient rainfall last night that washed away bigger particles and created space for faster dispersion without decline in temperature".

"AQI is back to 'very poor'. A slight increase in 'AQI' is predicted in next three days but it is likely to remain in very poor category," SAFAR said.

This is mainly due to the fact that surface winds are still low and temperature is likely to cool down, it said.

"Stubble fire is unlikely to impact Delhi air quality index (AQI) as fire counts are significantly down and winds are also flowing from other direction," SAFAR said in a report.