NEW DELHI: After a long haul of 22 days, the city’s air quality returned to the ‘poor’ zone on Tuesday. The city has so far been grappling with ‘very poor’ and ‘severe’ air quality. However, the relief is short-lived with air quality likely to deteriorate again from 25 November, as winds slow down and temperatures fall further with cold conditions setting in, said government agencies.
As per the Central Pollution Control Board (CPCB), Delhi’s overall air quality index (AQI) on Tuesday was 290 in the higher end of the ‘poor’ zone, as against 311, the previous day. The city’s AQI was recorded in the ‘poor’ zone last on 1 November. From 3 November, it has been fluctuating between ‘very poor’ and ‘severe’. The major spike was seen post-Diwali day, pushing it to ‘severe’ for the first time this season.
According to India Meteorological Department (IMD) officials, strong surface winds over the past two days helped in the dispersion of accumulated pollutants. The winds, however, are likely to slow down from November 24 onwards when air quality may go back to settle into ‘very poor’ zone.
“The pollution build-up since Diwali had not been cleared in the immediate days, as there was no system as such like a Western Disturbance. The dispersion is happening only now with strong surface winds. The wind speed is likely to weaken again from the evening of November 24, may push the air quality back to ‘very poor,” said a senior IMD scientist.
In the immediate days, the minimum temperature may increase as wind direction is likely to change to south-easterly. Also, now that farm fires in neighbouring states are almost ending, the pollution is mainly due to adverse meteorological conditions such as wind speed and cold conditions, he added.
The Indian Institute of Tropical Meteorology’s (IITM) decision support system showed that the share of Delhi’s transport emissions was highest (28%) while that of biomass burning was as low as (4%). The Council on Energy, Environment and Water (CEEW) data shows that fires are dipping with daily counts less than 500.
“With the reduction in farm fires, the emissions from local sources and unfavourable meteorological conditions will influence Delhi’s air quality in the coming days. The government should make use of insights from IITM’s early warning system to target local sources such as transport and road dust,” said Programme associate at CEEW L S Kurinji.