A general view of a polluted area in Delhi.
Credit: PTI Photo
Karnataka dominates the last of top 10 places in India with cleanest air, according to a report by Respirer Living Sciences and Climate Trends, which analysed the air quality data.
Topping this list is Aizawl in Mizoram, which had a PM2.5 concentration of 11 μg/m3, followed by Chikkamagaluru in Karnataka (17.6 μg/m3 ) and Mandikhera in Haryana (17.7 μg/m3).
In this report, Respirer Reports, an initiative of Respirer Living Sciences, analysed two sets of air quality data.
The first is the government’s PM2.5 data for the past one year (October 1, 2022 to September 30, 2023) to track improvement in air quality over the previous year in NCR and other cities listed in the National Clean Air Programme (NCAP). The other is PM2.5 data during winter, roughly between October and March, when pollution levels rise.
The list consists of all places covered by the government’s network of air quality monitors (CAAQMS), and not just the NCAP cities.
The seven other cities among the top 10 are: Chamarajanagar, Madikeri, Vijayapura, Raichur, Shivamogga, Gadag and Mysuru.
Pollution in Delhi
Delhi and other cities in the National Capital Region (NCR) still dominate air pollution rankings, according to the study.
Delhi’s air quality improved marginally, yet it was found to be the most polluted city between October 1, 2022 and September 30, 2023, with a PM2.5 concentration of 100.1 micrograms/cubic metre (μg/m3).
This is more than thrice the government’s ‘good’ level and 20 times the WHO’s safe limit, according to a statement from 'Respirer Reports’ and ‘Climate Trends’.
Two regions dominate the top 10 list of polluted cities in India from October 1, 2022- September 30, 2023 – Delhi-NCR and Bihar.
The five cities in NCR include -- Delhi, Faridabad, Ghaziabad, Noida and Meerut, and in Bihar -- Patna and Muzaffarpur.
The list also has Nalbari in Assam, Asansol in West Bengal, and Gwalior in Madhya Pradesh. Currently, Nalbari and Asansol have only one air quality monitor each, while Gwalior has three monitors that record the NCAP data.
Since NCAP’s launch in January 2019, the government has consistently added Continuous Ambient Air Quality Monitoring Stations (CAAQMS), from about 200 then to 517 currently. More measurement can lead to more hyperlocal insights, ultimately leading to improvements in city-level and airshed-level air quality.
Between October 1, 2022-September 30, 2023, Delhi recorded the highest PM2.5 levels in the country at 100.1 μg/m3, which is 3.3 times the CPCB’s ‘good’ level and 20 times the WHO’s safe limit. Delhi saw a 4 per cent improvement in air quality over the previous year, but Patna, in second place, witnessed a 24 per cent deterioration in air quality.
Aarti Khosla, Director, Climate Trends, said: “The analysis reflects that there has been improvement in the Indo-Gangetic Plain cities over the last few years. However, considering the enormous pollution load, these cities continue to experience the highest PM levels in the country. With NCAP nearing its first deadline, these studies highlight the data-level impact of policy action; however, deeper research is required to be able to attribute this improvement to sources of emissions and meteorological factors.”
Ronak Sutaria, Founder and CEO, Respirer Living Sciences, said: “The current report, released at the time when GRAP begins in the NCR, primarily tracks the trends in the NCAP cities during the past year and particularly during the peak pollution months. Key insights from the report show that Delhi’s air quality has improved annually (by 4 per cent) and during the peak pollution (October–December by 10 per cent) compared to the previous year. However, it still remains at the top of the most polluted cities list. The analysis for cities like Patna indicates that while the city’s air quality has deteriorated by 24 per cent over the last year, a closer look at the city’s monitors shows that just 1 of 6 monitors recorded worsening AQ by 86 per cent.”