The winter season this year is starting with much cleaner air compared to the last three years in Delhi, the Nation Capital Region and the Indo-Gangetic Plain region, according to an analysis by the Centre for Science and Environment (CSE). .
The analysis covers 156 continuous ambient air quality monitoring stations spread across 67 cities in Punjab, Chandigarh, Haryana, Delhi, Rajasthan, Uttar Pradesh, Bihar and West Bengal.
“The 2021 winter is starting with a cleaner threshold than the previous years, largely due to the intense and prolonged effect of the monsoons. How soon and intensely the winter pollution will hit us will depend on the scale and speed of action across the region and leveraging it for more sustained air quality gains,” said CSE executive director Anumita Roychowdhury.
This year, the number of farm fires pre-winter has been less than half of the last year count, and the lower number correlates well with the lower pollution in Delhi-NCR, according to the analysis.
But it has warned that the lower count, as reported by satellite imagery, could also be due to increased cloud cover, which prevents satellites from spotting fires.
During September and October this year, the number of days with ‘satisfactory’ levels of air quality has increased to 90%, compared with 43% in 2018.
However, it was 27% in 2020. A similar pattern is seen in the “moderately polluted” category, the CSE said.
‘Urgent action needed’
“Delhi and the larger region will require urgent action to prevent severe smog episodes and speed up deeper reforms to sustain the gains. Reduce traffic volume, eliminate waste burning, eliminate dirty industrial fuels, and implement stringent dust control measures, especially in the construction sector. Act now, and act decisively,” Ms. Roychowdhury said.
Air pollution in the city spikes during the winter season mainly because of the combined effect of stubble-burning in the neighbouring States and climatic conditions, that lower the wind speed and mixing height, thus trapping pollutants.
