As Diwali and winter approach, the air quality in Delhi has started to deteriorate. The average air quality index (AQI) moved into the ‘Poor’ zone on Thursday (October 10), and worsened progressively every day until Sunday — before improving marginally on Monday. The situation is not expected to get better this week.
The reason for the worsening of the air was the accumulation of pollutants after the burning of Ravan effigies on Dussehra on Tuesday, and a change in the wind direction, which brought in pollutants from Punjab and Haryana in the north-west, where the seasonal burning of crop residue is under way.
It ended a happy spell of three months, during which the air quality in the city oscillated between ‘Satisfactory’ and ‘Moderate’. In September, the highest AQI recorded was 173, which is considered ‘Moderate’; the lowest was 60, which is ‘Satisfactory’. The average AQI for the whole month was 98, in the ‘Satisfactory’ range — this is the lowest AQI the capital has had in the month of September since 2015.
The contribution from stubble burning to Delhi’s air in the form of particulate matter of 2.5 micrometres (PM2.5)started around Friday, and has increased since. Its share in the overall pollution increased from 1% on Friday to 8% on Monday.
The capital’s AQI is forecast to touch the higher end of the ‘Poor’ category on Tuesday at 297 — just four points less than the ‘Very poor’ air quality band. Further deterioration could start from the fourth week of October, with the burning of firecrackers around Diwali contributing to the bad air.
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