By Manoj Kumar N and Sunil Dahiya
Key highlights
- Compliance: In August 2024, 244 out of 245 cities with more than 80% of the days with CAAQMS data available, recorded PM2.5 concentrations below India’s NAAQS of 60 µg/m³. 68 cities complied with the WHO’s daily safe guideline concentration of 15 µg/m³.
- NCAP cities: The monthly average PM2.5 levels in 79 NCAP cities (out of 96 cities with more than 80% of days with data) surpassed the WHO’s daily guideline for PM2.5, while 95 cities met India’s daily NAAQS.
- Non-NCAP cities: Among the 149 non-NCAP cities with over 80% of days with CAAQMS data, 98 cities reported monthly average PM2.5 levels above the WHO daily guideline. All 149 cities adhered to the daily NAAQS.
- The surge in Indian cities meeting NAAQS and WHO standards is a direct result of the heavy August rains.
- AQI category: August 2024 experienced a substantial improvement in air quality, with 218 cities falling under the ‘Good’ category, higher than July’s 196 cities. July 2024 witnessed 50 cities classified as ‘Satisfactory’ and 4 as ‘Moderate’, while August saw a decline to 26 and 1, respectively. In August, no city fell into the ‘Poor’, ‘Very Poor’ or ‘Severe’ category.
- Delhi: Delhi recorded an average concentration of 27 µg/m³ with 24 days in the ‘Good’ category (0-30 µg/m³) and 7 days in the ‘Satisfactory’ category (31-60 µg/m³). This is the second cleanest August since 2016 after August 2020 which saw an average of 25 µg/m³. However, it is still twice the World Health Organization’s (WHO) daily guideline (15 µg/m³).
- Cleanest city: Tirupur, in the state of Tamil Nadu, was the cleanest city in India during August, with monthly average PM2.5 of 5 µg/m³.
- This marks the fifth consecutive time that Tirupur has ranked among the top 10 cleanest cities in the country.
- The top 10 cleanest cities comprise two cities each from Tamil Nadu, Uttar Pradesh, and Karnataka, and one city each from Madhya Pradesh, Bihar, Rajasthan, and Meghalaya.
- Most polluted city: Byrnihat in Assam/Meghalaya ranked as the most polluted city in India in August 2024, recording a monthly average PM2.5 concentration of 78 µg/m³, surpassing the daily National Ambient Air Quality Standards (NAAQS of 60 µg/m³) 53% of the days in the month.
- Frequency in top 10 polluted city: A total of 68 cities were featured in the daily top 10 most polluted cities list in August 2024. Of this, 22 made an appearance at least five times over the 31-day period, topped by Byrnihat in Assam/Meghalaya, which featured the most times (20 days), followed by Sri Ganganagar (19 days), Panipat (17 days), Mandi Gobindgarh (16 days), Jalna (16 days), Araria (14 days), Gurgaon (13 days), Bhagalpur (11 days), and Siwan (10 days).
- NCAP: Only 23 out of the 68 cities featured in the daily top 10 most polluted cities list during August 2024 are part of the National Clean Air Programme (NCAP). The remaining 45 have no action plan to reduce hazardous air pollution concentrations.
- Megacities: All megacities, such as Delhi, Chennai, Mumbai, Kolkata, and Bangalore, had PM2.5 concentrations below the daily NAAQS, with all days in August falling within the ‘Good’ and ‘Satisfactory’ category.
- Monitoring infrastructure: Three new continuous ambient air quality monitoring stations (CAAQMS) were installed in August 2024: one each in Pimpri-Chinchwad, Tirunelveli, and Durgapur. This increased the national total to 550 stations. Tirunelveli city received its first station while other two cities had already installed CAAQMS.
Monthly ambient air quality snapshot for India: August 2024
Monthly ambient air quality trends in India: August 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).