Delhi has had its cleanest start to winter in years, shows report
New Delhi The Centre for Science and Environment (CSE) on Thursday released an analysis of winter pollution in Delhi since 2015, finding that this October has had the cleanest start to the winter season with respect to PM 2.5 presence since the data was compiled. For the purpose of the study, CSE analysed PM 2.5 concentration for the period starting January 1, 2015 to October, 17, 2022, with winter being defined as the period between October 1 and February 28 in any given year. The analysis used real-time data available from the current working air quality monitoring stations in Delhi-NCR, covering 81 continuous ambient air quality monitoring stations (CAAQMS) spread across the region. Anumita Roychowdhury, executive director, research and advocacy at CSE, said this clean start to the winter has largely been due to extended rainfall. “If we analysed the air quality index (AQI) only based on PM 2.5 concentration, then there were a total of five good air days in the first two weeks of October this year. However, the PM 2.5 concentration has quickly risen since then and has already touched ‘poor’ levels, crossing the 90 micrograms per cubic metre concentration,” Roychowdhury said. The CSE analysis also showed that the last three winter seasons in Delhi had a marked improvement compared to the winters between 2015 and 2018 -- the winter seasons of 2019-20, 2020-21 and 2021-22 averaged a PM 2.5 concentration of 150-160 micrograms per cubic metre, while it was around 180-190 micrograms in the winters from 2015-2018, the analysis said.. The winter PM 2.5 average for 2021-22 was found to be 10-30% lower on average when compared to the winter of 2020-21. Ghaziabad registered a 30% improvement -- the highest among NCR cities – followed by Greater Noida (28%), Noida (23%), Faridabad (16%), Delhi (12% and Gurugram (11%). These levels, however, are still 2.5 times the national 24-hour standard of 60 micrograms per cubic metres.
