Authors: Manoj Kumar N and Sunil Dahiya
Key highlights
- Byrnihat in Assam/Meghalaya ranked as the most polluted city in India in July 2024, recording a monthly average PM2.5 concentration of 90 µg/m³, surpassing the daily National Ambient Air Quality Standards (NAAQS) 70% of the days in the month. Among India’s top 10 polluted cities, three were located in Rajasthan, two each in Bihar and Haryana, while Punjab, Assam, and Uttar Pradesh each had one.
- Ranking as India’s 26th most polluted city in July 2024, Delhi’s PM2.5 pollution levels at 40 µg/m³ were just equivalent to the annual NAAQS but eight times the World Health Organization’s (WHO) annual guideline.
- Other megacities, such as Chennai, Mumbai, Kolkata and Bangalore, had PM2.5 concentrations below the annual NAAQS, with all days in July falling within the ‘Good’ category (0-30 µg/m³).
- A total of 61 cities were featured in the daily top 10 most polluted cities list in July 2024. Of this, 23 made an appearance at least five times over the 31-day period, topped by Byrnihat in Assam/Meghalaya, which featured the most times (21 days), followed by Mandi Gobindgarh (17 days), Sri Ganganagar (15 days), Muzaffarpur (14 days), Faridabad (14 days), Dholpur (13 days), Dungarpur (12 days), Munger (10 days), Muzaffarnagar (10 days), and Rohtak (10 days).
- Only 20 out of the 61 cities featured in the daily top 10 most polluted cities list during July 2024 are part of the National Clean Air Programme (NCAP). The remaining 41 have no action plan to reduce hazardous air pollution concentrations.
- Two new continuous ambient air quality monitoring stations (CAAQMS) were installed in July 2024: one each in Pune and Asansol. This increased the national total to 547 stations.
- In July 2024, 226 out of 250 cities, with more than 80% of the days with CAAQMS data, recorded PM2.5 concentrations below India’s annual NAAQS of 40 µg/m³. Only five cities complied with the WHO’s annual safe guideline concentration of 5 µg/m³.
- In July 2024, the monthly average PM2.5 levels in all NCAP cities (out of 98 cities with more than 80% of days with data) surpassed the WHO’s annual guideline for PM2.5, while 90 cities met India’s annual NAAQS.
- Among the 152 non-NCAP cities with over 80% of days with CAAQMS data, 147 cities reported monthly average PM2.5 levels above the WHO annual guideline. 136 cities adhered to the annual NAAQS, while the air quality in the remaining 16 cities was poorer than the annual NAAQS.
- July 2024 experienced a substantial improvement in air quality, with 196 cities falling under the ‘Good’ category, a stark contrast to June’s 130 cities. June 2024 witnessed 98 cities classified as ‘Satisfactory’ and 20 as ‘Moderate’, while July saw a slight decline to 50 and 4, respectively. In July, no city fell into the ‘Poor’, ‘Very Poor’ or ‘Severe’ category.
- The improvement in air quality during July 2024 can be largely credited to increased rainfall. Rain helps in washing down the pollutants from the atmosphere, leading to cleaner air. This natural cleansing process results in a higher number of cities being classified under the ‘Good’ category.
Monthly ambient air quality snapshot for India: July 2024
Monthly ambient air quality trends in India: July 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).