India monthly ambient air quality snapshot: March 2024

Authors: Manoj Kumar N and Sunil Dahiya

Key highlights

  • In March 2024, 204 out of 257 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) but only one complied with the  World Health Organization’s daily safe guideline concentration of 15 µg/m³.
    • In March 2024, the monthly average PM2.5 levels in 97 National Clean Air Programme (NCAP) cities surpassed the WHO’s daily guideline for PM2.5, while 77 cities met India’s daily National Ambient Air Quality Standards (NAAQS).
    • Among the 159 non-NCAP cities with over 80% of days with CAAQMS data, no city reported monthly average PM2.5 levels below the WHO daily guideline. 127 cities adhered to the daily NAAQS, while the air quality in the remaining 32 cities was poorer than the NAAQS.
  • In March 2024, there was a significant improvement in air quality, with 163 cities falling into the ‘Satisfactory’ category, marking a notable increase from 124 cities in the category during the previous month. The ‘Good’ category also saw a substantial rise to 43 cities from 36 cities in February. Conversely, the count of cities in the ‘Poor’ and ‘Very Poor’ categories decreased to just 1 city each for March from 24 and 3, respectively, for February. Notable declines were observed in the ‘Moderate’ category, with 49, down from 66 in February. 
  • Byrnihat ranked as the most polluted city in India in March 2024, making it the second consecutive month that the city topped the list. Byrnihat recorded a monthly average PM2.5 concentration of 155 µg/m³, surpassing the daily NAAQS on 29 days out of 31 days with data for the month. Among India’s top 10 polluted cities, three were in Assam, two in Haryana, and one each in Uttar Pradesh, Gujarat, Rajasthan, Tripura, and Maharashtra.
  • Delhi was India’s 17th most polluted city in March 2024, but its pollution levels were still higher than the NAAQS and nearly five times the WHO daily guideline levels.
  • A total of 66 cities were featured in the daily most polluted cities list in March 2024. 22 out of those made an appearance at least five times over the 31-day period, topped by Byrnihat in Meghalaya/Assam, featuring the most times (25 days), followed by Nandesari (17 days), Nalbari (14 days), Guwahati (13 days),  Agartala (10 days), Hanumangarh (10 days), and Chhapra (10 days).
  • The cities featured in the daily top 10 most polluted cities list in India were spread across 15 states and union territories (UT).
  • Only 26 out of the 66 cities featured in the daily top 10 most polluted cities list during March 2024 are part of NCAP, while the remaining 40 cities still don’t have 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 March 2024, leaving 30 other identified NCAP cities without any transparent information on real-time pollution levels.

No new monitoring station was installed during March 2024. Currently, there are 540 CAAQMS that cover 281 cities.

Out of the total of 281 cities, only 257 cities had more than 80% of the days in March with data availability, leaving 14 cities with less than 80% days with data and 10 cities where no data was collected even though CAAQMS were installed in those cities.

NCAP cities

In March 2024, the monthly average PM2.5 levels in 97 NCAP cities surpassed the WHO’s daily guideline for PM2.5. Only 77 cities met India’s daily National Ambient Air Quality Standards (NAAQS), with the remaining 21 cities recording PM2.5 concentrations exceeding the NAAQS; among these,  Byrnihat on the Meghalaya/Assam border recorded PM2.5 levels two times higher than the daily recommended standard of 60 µg/m³.

Non-NCAP cities

Among the 159 non-NCAP cities with over 80% of days with CAAQMS data in March 2024, no city reported monthly average PM2.5 levels below the WHO daily guideline.

127 cities adhered to the daily NAAQS, while the air quality in the remaining 32 cities was poorer than the NAAQS.


Air pollution levels and National Clean Air Programme (NCAP)

NCAP cities

In March 2024, only thirty out of the 98 NCAP cities complied with the daily NAAQS standard for PM2.5 on all days of the month.

Additionally, 68 out of the 98 NCAP cities consistently recorded PM2.5 levels exceeding the WHO-prescribed daily guideline levels every day of the month.

Non-NCAP cities

Among the 159 non-NCAP cities, only 59 cities experienced 100% compliance with the daily NAAQS for all days of the month. Also, 30 cities recorded PM2.5 levels surpassing the daily NAAQS for 50% of the days in March.

122 out of the 159 non-NCAP cities consistently recorded PM2.5 levels above the prescribed daily WHO guideline on all days of the month.

In February 2024, 124 cities fell within the ‘Satisfactory’ category, and 66 cities in the ‘Moderate’ category. There were also significant numbers of cities in the ‘Good’ and ‘Poor’ categories, 36 and 24 cities, respectively. Additionally, 3 cities were classified as ‘Very Poor.’

However, in March 2024, there was a noticeable improvement in air quality, with 163 cities falling within the ‘Satisfactory’ category, indicating a significant increase from February. The number of cities in the ‘Good’ category also saw a substantial rise to 43, reflecting a positive trend. While the count of cities in the ‘Moderate’ category decreased to 49, there was a notable decline in the number of cities classified as ‘Poor’ and ‘Very Poor’, with only one city in each category.


Ranking of the top 10 most polluted and cleanest cities in India

Byrnihat ranked as the most polluted city in India in March 2024, recording a monthly average PM2.5 concentration of 155 µg/m³, surpassing the daily NAAQS 94% days in the month. This is the second consecutive month the city has topped the list of most polluted cities.

Following Byrnihat, the other cities in the top 10 most polluted list for March were Nandesari, Guwahati, Ballabgarh, Gurgaon, Muzaffarnagar, Dholpur, Agartala, Parbhani, and Nalbari, respectively, from the second to the tenth positions. 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 National Clean Air Programme (NCAP).

Among India’s top 10 polluted cities, three were in Assam, two in Haryana, and one each in Uttar Pradesh, Gujarat, Rajasthan, Tripura, and Maharashtra.

Parbhani, one of the top 10 most polluted cities, lacked comparable PM2.5 concentrations from CAAQMS for the corresponding month last year.

Among the remaining nine cities, Seven recorded higher PM2.5 concentrations in March 2024 compared to the same month last year.

However, there was a slight reduction observed in Byrnihat and Agartala cities.

Additionally, the frequency of ‘Severe’ air quality days reduced in Byrnihat, but notably increased under the category of ‘Very Poor’ air quality days in March 2024 compared to March 2023

A total of 66 cities were featured in the daily most polluted cities list in March 2024. 22 out of those made an appearance at least five times over the 31-day period, topped by Byrnihat in Meghalaya/Assam, featuring the most times (25 days), followed by Nandesari (17 days), Nalbari (14 days), Guwahati (13 days),  Agartala (10 days), Hanumangarh (10 days), and Chhapra (10 days).

The cities featured in the daily top 10 most polluted cities list in India were spread across 15 states and union territories (UT), i.e, Assam, Gujarat, Tripura, Rajasthan, Bihar, Maharashtra, Odisha, Haryana, Karnataka, Punjab, Uttar Pradesh, Himachal Pradesh, Madhya Pradesh, West Bengal and Andhra Pradesh, showing the widespread severity of hazardous air pollution levels nationally.

Only 26 out of the 66 cities featured in the daily top 10 most polluted cities list during March 2024 are part of the NCAP, while the remaining 40 cities still don’t have any action plan to reduce hazardous air pollution concentrations.

Varanasi in Uttar Pradesh emerged as the cleanest city in India in March 2024, recording a monthly average PM2.5 concentration that placed all 31 days in the ‘good’ category (PM2.5 concentration lower than 30 µg/m³). Also, Varanasi recorded PM2.5 concentrations below the WHO daily guideline level of 15 µg/m³. Following closely behind were Korba in Chhattisgarh and Vijayapura in Karnataka.

Additionally, other cities featured in the top 10 cleanest cities list for March 2024, included Bareilly, Barmer, Mandikhera, Chamarajanagar, Raichur, Palkalaiperur, and  Surat.

Among India’s top 10 cleaner cities, three were in Karnataka, two in Uttar Pradesh, and one each in Chhattisgarh, Rajasthan, Haryana, Gujarat, and Tamil Nadu.

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 March 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 inactive stations, as was the case in Sikkim.

In March 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 13 capitals lacked real-time data on air pollution levels.

Among the 23 capitals with monitoring systems, five cities exhibited air quality surpassing the daily NAAQS set by the Central Pollution Control Board (CPCB).

All capitals recorded monthly average PM2.5 concentrations exceeding the daily level recommended by the World Health Organization (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 March 2024; others didn’t have CAAQMS installed, i.e., Saharanpur, Ranchi, and Jamshedpur.

Five out of 19 cities exceeded NAAQS, and these cities are located in Delhi, Bihar, West Bengal, Haryana, and Chandigarh.

Notably, all cities in Uttar Pradesh had PM2.5 concentration levels below the NAAQS.


Air pollution across megacities in India- March 2024


Monthly ambient air quality trends in India: March 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).


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