In a first in 5 years, Delhi sees no ‘smog episodes’ in Oct and Nov: Analysis
This year, Delhi recorded two consecutive days when the AQI was ‘severe’ in the first week of November, Central Pollution Control Board data shows.
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The oldest air quality monitoring stations from which data was used include ones at Anand Vihar, IGI airport, Mandir Marg, Punjabi Bagh, RK Puram and Shadipur. (Express File) This October and November, Delhi saw no severe, prolonged ‘smog episodes’, a first for the city in the past five years, as per an analysis by the Centre for Science and Environment (CSE).
According to Avikal Somvanshi, programme manager at CSE’s Urban Lab, the analysis considers a severe smog episode to be when PM2.5 or PM10 concentrations of 300µg/m3 or 500 µg/m3 respectively persist for three days, which is old Graded Response Action Plan’s ‘severe +’ category. The analysis stated that there is “usually one smog episode during October-November lasting 6-10 days”, and last winter, there were two smog episodes in November with one lasting 10 days from November 4-13.
This year, Delhi recorded two consecutive days when the AQI was ‘severe’ in the first week of November, Central Pollution Control Board data shows.
Data from the city’s 10 oldest air quality monitoring stations also showed that October and November this year were the least polluted in terms of PM 2.5 levels in the past eight years, as per the analysis. The average PM 2.5 level at these 10 stations in the two months was 135 µg/m3, lower than 181 µg/m3 for these months in 2015. In 2016 and 2017, the average was over 200 µg/m3. In 2021, this figure was 153 µg/m3.
The oldest air quality monitoring stations from which data was used include ones at Anand Vihar, IGI airport, Mandir Marg, Punjabi Bagh, RK Puram and Shadipur.
The analysis also noted that Delhi fared worse than other major cities in NCR. Across 37 air quality monitoring stations, the average PM 2.5 level in October and November in Delhi was 142 µg/m3. This is worse than other major NCR cities – Gurgaon (134 µg/m3), Ghaziabad (131 µg/m3), Faridabad (129 µg/m3), Greater Noida (126 µg/m3) and Noida (109 µg/m3). Among 16 air pollution ‘hotspots’ in NCR, Jahangir-puri fared the worst with an average PM 2.5 level of 186 µg/m3.
Somvanshi said the 16 hotspots were listed by the erstwhile Environment Pollution (Prevention and Control) Authority (EPCA). Thirteen of these were in Delhi (Anand Vihar, Wazirpur, Mundka, Mandir Marg, Rohini, RK Puram, Okhla Phase 2 etc) and four were in other parts of the NCR (Gurgaon, Faridabad, Sahibabad and Bahadurgarh).
The analysis also noted that the most polluted locations in NCR continue to be within Delhi. “Burari Crossing has been the most polluted location in NCR with October-November average of 200 µg/m3,” it stated. Mandikhera and Palwal in South Haryana were found to be the least polluted locations in the NCR.
The analysis attributes the improvement in air quality this year to factors including meteorological conditions, an early Diwali and lower smoke intrusion from farm fires.
Among meteorological factors, high wind speed and rainfall helped disperse pollutants. Rainfall in October, for instance, brought five days when the PM 2.5 level was less than 30 µg/m3. It also notes that the farm fire count in Punjab and Haryana was lower this year compared to 2021 and meteorological conditions were less conducive for the transport of pollutants from stubble burning.
It added: “Stronger pre-emptive measures and deeper round-the-year action on local sources is needed to bring down the winter pollution to a satisfactory level.”
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