Authors: Manoj Kumar N and Sunil Dahiya
Key highlights
- In May 2024, 212 out of 254 cities with more than 80% of the days with continuous ambient air quality monitoring station (CAAQMS) data recorded PM2.5 concentrations below India’s daily National Ambient Air Quality Standards (NAAQS) of 60 µg/m³. Only twelve complied with the World Health Organization’s daily safe guideline concentration of 15 µg/m³.
- In May 2024, the monthly average PM2.5 levels in 94 National Clean Air Programme (NCAP) cities (out of 98 cities with more than 80% days with data) surpassed the World Health Organisation’s (WHO) daily guideline for PM2.5, while 83 cities met India’s daily NAAQS.
- Among the 156 non-NCAP cities with over 80% of days with CAAQMS data, eight cities reported monthly average PM2.5 levels below the WHO daily guideline. 129 cities adhered to the daily NAAQS, while the air quality in the remaining 27 cities was poorer than the NAAQS.
- May 2024 experienced a considerable improvement in air quality, with 98 cities falling under the ‘Good’ category, a stark contrast to April’s 65 cities. Despite this progress, there was a rise in the number of cities categorized as ‘Poor,’ increasing from six in April to eleven in May. April 2024 witnessed 150 cities classified as ‘Satisfactory’ and 33 as ‘Moderate,’ while May saw a slight decline to 114 and 31, respectively.
- Faridabad in Haryana ranked as the most polluted city in India in May 2024, recording a monthly average PM2.5 concentration of 119 µg/m³, surpassing the daily NAAQS 100% of the days in the month. Among India’s top 10 polluted cities, three were located in Haryana, two in Rajasthan and Uttar Pradesh each, while Punjab, Assam, and Bihar each had one.
- Ranking as India’s 11th most polluted city in May 2024, Delhi’s pollution levels exceeded the NAAQS and were about six times the WHO daily guideline levels. May 2024 was also the most polluted May in Delhi compared to previous years going back to 2018.
- A total of 50 cities were featured in the daily most polluted cities list in May 2024. Of this, 24 made an appearance at least five times over the 31-day period, topped by Faridabad in Haryana, which featured the most times (22 days), followed by Sri Ganganagar (20 days), Byrnihat (18 days), Bhiwadi (17 days), Ballabgarh (17 days), Muzaffarnagar (16 days), Gurgaon (15 days), Greater Noida (14 days), Banswara (13 days), Mandigobindgarh (13 days), and Delhi (12 days).
- In May 2024, the cities featured in the daily top 10 most polluted cities list in India were spread across 14 states and union territories (UT), reiterating how widespread and severe toxic air is across the country.
- Only 16 out of the 50 cities featured in the daily top 10 most polluted cities list during May 2024 are part of the NCAP. The remaining 34 are devoid of any action plan to reduce hazardous air pollution concentrations.
Ambient air quality monitoring network
Only 101 of the 131 non-attainment cities under the National Clean Air Programme (NCAP) have a CAAQMS installed as of May 2024. The remaining 30 cities do not provide any transparent information on real-time pollution levels.
Of the 281 cities with CAAQMS, 27 did not record data for more than 24 days (80%) in May 2024, 13 of which did not record even for one single day.
NCAP cities
In May 2024, the monthly average PM2.5 levels in 94 NCAP cities surpassed the WHO’s daily guideline for PM2.5. Only 83 NCAP cities met India’s daily National Ambient Air Quality Standards (NAAQS) set by the Central Pollution Control Board (CPCB), with the remaining 15 cities recording PM2.5 concentrations exceeding the NAAQS.
Non-NCAP cities
Among the 156 non-NCAP cities with over 80% of days with CAAQMS data in May 2024, only eight cities reported monthly average PM2.5 levels below the WHO daily guideline.
129 cities adhered to the daily NAAQS, while the air quality in the remaining 27 cities was poorer than the NAAQS.
Air pollution levels and National Clean Air Programme (NCAP)
NCAP cities
In May 2024, only 46 out of the 98 NCAP cities complied with the daily NAAQS standard for PM2.5 on all days of the month.
Additionally, 63 out of the 98 NCAP cities consistently recorded PM2.5 levels exceeding the WHO daily guideline levels every day of the month.
Non-NCAP cities
Among the 156 non-NCAP cities, only 74 cities experienced 100% compliance with the daily NAAQS for all days of the month. Also, 25 cities recorded PM2.5 levels surpassing the daily NAAQS for 50% of the days in May.
Of the 156 non-NCAP cities, 85 consistently recorded PM2.5 levels above the prescribed daily WHO guideline on all days of the month.
In April 2024, 150 cities fell within the ‘Satisfactory’ category, with 65 cities in the ‘Good’ category. Additionally, there were 33 cities in the ‘Moderate’ category and six cities under ‘Poor category’ . There was one city classified as ‘Very Poor’.
However, in May 2024, there was a noticeable improvement in air quality, with 98 cities falling within the ‘Good’ category, indicating a significant increase from April. The number of cities in the ‘Satisfactory’ category slightly decreased to 114. The number of cities in the ‘Moderate’ category also decreased to 31, but there was a notable increase of eleven cities classified as ‘Poor’. There were no cities under the ‘Very Poor’ category.
Ranking of the top 10 most polluted and cleanest cities in India
Faridabad ranked as the most polluted city in India in May 2024, recording a monthly average PM2.5 concentration of 119 µg/m³, surpassing the daily NAAQS on all days in the month.
Following Faridabad, the other cities in the top 10 most polluted list for May were Byrnihat, Bhiwadi, Sri Ganganagar, Muzaffarnagar, Buxar, Gurgaon, Mandigobindgarh, Ballabgarh, and Greater Noida, respectively. Notably, three NCAP and seven non-NCAP cities were included in this list, underscoring the widespread issue of hazardous air quality across cities beyond the current focus list of non-attainment cities under the NCAP.
Among India’s top 10 polluted cities, three were located in Haryana, two in Rajasthan and Uttar Pradesh each, while Punjab, Assam, and Bihar each had one.
Buxar, one of the top 10 most polluted cities, lacked comparable PM2.5 concentrations from CAAQMS for the corresponding month last year.
Eight out of the top 10 most polluted cities recorded a higher PM2.5 concentration this May compared to May 2023.
Byrnihat is the only city in the Top 10 list that recorded a lower concentration compared to last year. However, this concentration is still seven times higher than WHO standards.
Also, three out of ten most polluted cities (Faridabad, Byrnihat and Mandigobindgarh) are under the NCAP.
A total of 50 cities were featured in the daily most polluted cities list in May 2024. Of them, 24 made an appearance at least five times over the 31-day period, topped by Faridabad in Haryana featuring the most times (22 days), followed by Sri Ganganagar (20 days), Byrnihat (18 days), Bhiwadi (17 days), Ballabgarh (17 days), Muzaffarnagar (16 days), Gurgaon (15 days), Greater Noida (14 days), Banswara (13 days), Mandigobindgarh (13 days), Delhi (12 days).
The daily top 10 most polluted cities were spread across 14 states and union territories (UT), demonstrating how widespread and severe toxic air is across the country. The 14 states and UTs are: Haryana, Rajasthan, Assam, Uttar Pradesh, Punjab, Delhi, Bihar, Madhya Pradesh, Gujarat, West Bengal, Andhra Pradesh, Uttarakhand, Maharashtra, and Odisha.
Only 16 out of the 50 cities featured in the daily top 10 most polluted cities list during May 2024 are part of the NCAP, while the remaining 34 cities still don’t have any action plan to reduce hazardous air pollution concentrations.
Aizawl in Mizoram emerged as the cleanest city in India in May 2024, recording a monthly average PM2.5 concentration that placed all 31 monitored days in the ‘good’ category (PM2.5 concentration lower than 30 µg/m³).
Additionally, other cities featured in the top 10 cleanest cities list for May 2024 included Tirupur, Haldia, Ramanathapuram, Belgaum, Palkalaiperur, Varanasi, Puducherry, Raichur, and Koppal.
Notably all cities in the top 10 had PM2.5 average below the WHO guidelines.
Among the 36 states and union territories (UT) in India, only 29 had at least one city with a functioning CAAQMS providing data for more than 80% of the days in May 2024.
The remaining territories either lacked any installed CAAQMS, such as Andaman and Nicobar Islands, Dadra and Nagar Haveli and Daman and Diu, Goa, Ladakh, and Lakshadweep, or had less than 80% data, as was the case in Srinagar and Gangtok.
In May 2024, 23 out of 36 state/UT capital cities had at least one CAAQMS installed, with data availability exceeding 80% of the days. However, the remaining capitals lacked real-time data on air pollution levels.
Among the 23 capitals with monitoring systems, four cities exhibited air quality surpassing the daily NAAQS set by the CPCB.
All capitals, except Puducherry and Aizawl, recorded monthly average PM2.5 concentrations exceeding the daily level recommended by the WHO.
Air pollution across cities with million plus population in Indo-Gangatic Plains (IGP)
Out of 22 million plus cities across Indo-Gangetic Plain (IGP) states/UTs (Punjab, Chandigarh, Haryana, Delhi, Uttar Pradesh, Bihar, Jharkhand and West-Bengal), only 19 cities had an operational CAAQMS for more than 80% of the days in May 2024; others didn’t have CAAQMS installed, i.e., Saharanpur, Ranchi, and Jamshedpur.
Ten out of 19 cities exceeded NAAQS, and these cities are located in Delhi, Bihar, West Bengal, Haryana, Uttar Pradesh, Punjab and Chandigarh.
Air pollution across megacities in India- March 2024
Monthly ambient air quality trends in India: May 2024 air quality snapshot (pdf version)
Data sources
Ambient air quality data recorded by Continuous Ambient Air Quality Monitoring Stations (CAAQMS) is downloaded from the ‘Central Control Room for Air Quality Management – All India‘ dashboard operated by the Central Pollution Control Board (CPCB).