By Manoj Kumar N and Nandikesh Sivalingam
Key highlights
- Compliance: In October 2024, 214 out of 263 cities with more than 80% of the days with continuous ambient air quality monitoring stations (CAAQMS) data available, recorded PM2.5 concentrations below India’s National Ambient Air Quality Standards (NAAQS) of 60 µg/m³. 13 cities complied with the World Health Organization’s (WHO) daily safe guideline concentration of 15 µg/m³.
- NCAP cities: The monthly average PM2.5 levels in 96 National Clean Air Programme (NCAP) cities (out of 97 cities with more than 80% of days with data) surpassed the WHO’s daily guideline for PM2.5, while 79 cities met India’s daily NAAQS.
- Non-NCAP cities: Among the 166 non-NCAP cities with over 80% of days with CAAQMS data, 154 cities reported monthly average PM2.5 levels above the WHO daily guideline. 135 cities adhered to the daily NAAQS.
- The number of cities exceeding daily WHO standards rose to 250 in October, up from 220 in September.
- AQI category: In October 2024, the number of cities with ‘Good’ (0-30 µg/m³) air quality dropped to 79 from 201 in September. The number of cities with ‘Satisfactory’ (31-60 µg/m³) air quality increased from 59 to 135. Additionally, 44 cities experienced ‘Moderate’ (61-90 µg/m³) air quality in October, compared to just four cities in September. This shift of cities into the moderate category is widespread across the Indo-Gangetic Plain, particularly in and around the National Capital Region.
- Most polluted city: Delhi ranked as the most polluted city in India in October 2024, recording a monthly average PM2.5 concentration of 111 µg/m³, surpassing the daily NAAQS limit of 60 µg/m³ 84% of the days in the month.
- Delhi recorded 9 days in the ‘Good’ category, 5 days in the ‘Satisfactory’ category, 8 days in the ‘Moderate’ category, 4 days in the ‘Poor’ (91-120 µg/m³) category and 14 days in the ‘Very Poor’ (121-250 µg/m³) category.
- October average is 2.5 times higher than September’s average of 43 µg/m³, when there were 9 days in the ‘Good’ category, 16 days in the ‘Satisfactory’ category, 4 days in the ‘Moderate’ category, and 1 day in the ‘Very Poor (121-250)’ category.
- Although the average contribution from stubble burning to PM2.5 levels in Delhi was less than 10% in October, the increased PM2.5 concentration indicates contributions from year-round sources, highlighting the need for a long-term plan instead of a short term winter plan.
- Uttar Pradesh dominated India’s top 10 most polluted cities in October 2024, followed by 2 in Haryana, and 1 in Bihar, and Delhi, for a total of 6 cities on the list.
- All 10 of India’s most polluted cities are located within the National Capital Region (NCR).
- Cleanest city: Aizawl, in the state of Mizoram, was the cleanest city in India during October, with a monthly average PM2.5 of 6 µg/m³.
- The top 10 cleanest cities comprise 5 cities from Karnataka, 4 from Tamil Nadu, and 1 city from Mizoram.
- All cities in peninsular states covering Kerala, Tamil Nadu, Karnataka, Andhra Pradesh, Telangana and Maharashtra were either in ‘Good’ or ‘Satisfactory’ category due to the southwest and northeast monsoons.
- Frequency in top 10 polluted cities: A total of 65 cities were featured in the daily top 10 most polluted cities list in October 2024. Of these, 21 cities made an appearance at least five times over the 31-day period, topped by Ghaziabad in Uttar Pradesh, which featured the most times (24 days), followed by Hapur (20 days), Muzaffarnagar (20 days), Delhi (19 days), Byrnihat (13 days), and Hajipur (11 days).
- NCAP: Only 22 out of the 65 cities featured in the daily top 10 most polluted cities list during October 2024 are part of the National Clean Air Programme (NCAP). The remaining 43 cities have no action plan to reduce hazardous air pollution concentrations.
- Megacities: With the exception of Delhi, all other megacities, such as Chennai, Mumbai, Kolkata, and Bangalore, saw all their monthly averages in October falling within the NAAQS.
- Monitoring infrastructure: In October 2024, eight new continuous ambient air quality monitoring stations (CAAQMS) were installed, with seven in Tamil Nadu and one in West Bengal. This marks the highest number of CAAQMS installations in a single month this year, raising the national total from 551 to 559 stations and expanding coverage from 282 to 289 cities.
Monthly ambient air quality snapshot for India: October 2024
Monthly ambient air quality trends in India: October 2024 air quality snapshot (pdf version)
Press release – Monthly ambient air quality trends in India: October 2024 air quality snapshot
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).