Bengaluru shows consistently low PM2.5 levels compared to other cities, says report

A new report states that Bengaluru shows consistently low PM2.5 levels compared to other cities and stands out for maintaining the lowest and most stable air quality.

The report, ‘Meteorology-Driven Persistence of PM2.5 Pollution in Indian Cities: Implications for NCAP Phase-III’, by Climate Trends, analyses how meteorological conditions influence the persistence of PM2.5 pollution across six major Indian cities: Delhi, Patna, Kolkata, Mumbai, Chennai, and Bengaluru.

On CPCB data

The report is based on the Central Pollution Control Board’s (CPCB) air quality monitoring data from 2024–2025, and the analysis integrates station-averaged CPCB observations with meteorological clustering to characterise PM2.5 behaviour across monthly, seasonal, and regime-specific scales.

“Bengaluru shows consistently low PM2.5 levels compared to other cities. Median concentrations remain relatively stable, with only a slight increase during the winter months. The narrow interquartile ranges across most months indicate low variability and fewer extreme pollution events, making Bengaluru the least polluted city among those analysed,” the report states.

It added that the seasonal mean PM2.5 concentrations in Bengaluru indicate comparatively better air quality than northern cities, with clear seasonal variability across both years.

According to the report in 2024, the seasonal mean values were 37.4 micrograms per cubic meter (μg/m3) in the winter, 35.7 μg/m3 in the summer, 15.7 μg/m3 during the monsoon, and 33.3 μg/m3 in the post-monsoon season.

During colder months

“In 2025, winter pollution increased to 42.4 μg/m3, indicating slightly poorer air quality during colder months, while significant improvements were observed in other seasons. The summer mean dropped sharply to 24.7 μg/m3, the monsoon mean declined further to 13.4 μg/m3, and the post-monsoon mean reduced to 28.6 μg/m3, reflecting overall seasonal improvement outside winter in 2025,” the report states.

The monthly average PM2.5 values further illustrate these patterns.

In 2024, the highest monthly mean was observed in March (46.2 μg/m3), followed by January (39.6 μg/m3) and February (39.4 μg/m3), while the cleanest months were June and July (both ~11-12 μg/m3) due to the monsoon influence.

In 2025, most months recorded lower mean values compared to 2024, particularly in April (26.9 μg/m3) and May (15.2 μg/m3).

However, winter months showed mixed trends, with January (40.4 μg/m3) remaining high and a sharp increase in December (52.2 μg/m3), the highest monthly mean across both years.

“Overall, the mean PM2.5 levels suggest that Bengaluru experienced cleaner air in 2025 during summer, monsoon, and post-monsoon seasons, although episodic winter pollution remains a concern,” the report stated.

Delhi highest

The report identifies Delhi as the most severely polluted city, recording the highest annual PM2.5 levels and extended periods of severe air quality in winter. Patna emerges as the second-most polluted city, while Mumbai and Chennai saw a rise in annual pollution levels in 2025.