The report is based on Central Pollution Control Board air quality monitoring data from 2024-2025. | Photo credit: File Photo
A new report says 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 analyzes how meteorological conditions affect the persistence of PM2.5 pollution in six major Indian cities: Delhi, Patna, Kolkata, Mumbai, Chennai and Bengaluru.
On CPCB data
The report is based on Central Pollution Control Board (CPCB) air quality monitoring data from 2024-2025, and the analysis integrates station-averaged CPCB observations with meteorological clustering to characterize the behavior of PM2.5 at monthly, seasonal and regime-specific scales.
“Bengaluru shows consistently low levels of PM2.5 compared to other cities. Median concentrations remain relatively stable, with only a slight increase during the winter months. Narrow interquartile ranges in most months indicate low variability and less extreme pollution, making Bengaluru the least polluted city among those analyzed,” the report said.
He added that Bengaluru’s seasonal average PM2.5 concentrations indicate comparatively better air quality than cities in the north of the country, with clear seasonal variability in both years.
According to the 2024 report, seasonal averages were 37.4 micrograms per cubic meter (μg/m3) in winter, 35.7 μg/m3 in summer, 15.7 μg/m3 during monsoon and 33.3 μg/m3 in post-monsoon.
During the colder months
“In 2025, winter pollution increased to 42.4 μg/m3, indicating slightly worse air quality during the colder months, while significant improvements were observed in other seasons. The summer average dropped sharply to 24.7 μg/m3, the monsoon average further decreased to 13.4 μg/m3, and after the monsoon, the overall improvement in the winter season decreased to 28.6 μg/m3. 2025,” the report states.
These patterns further illustrate the monthly average values of PM2.5.
In 2024, the highest monthly average was observed in March (46.2 μg/m3), followed by January (39.6 μg/m3) and February (39.4 μg/m3), with the cleanest months being June and July (both ~11-12 μg/m3) due to the monsoon.
In 2025, lower average values compared to 2024 were recorded in most months, especially in April (26.9 μg/m3) and May (15.2 μg/m3).
However, the winter months showed mixed trends, with January (40.4 μg/m3) remaining high and a spike in December (52.2 μg/m3), the highest monthly average in both years.
“Overall average PM2.5 levels indicate that Bengaluru experienced cleaner air in 2025 during the summer, monsoon and post-monsoon seasons, although occasional winter pollution remains a problem,” the report said.
Delhi highest
The report identifies Delhi as the most severely polluted city, recording the highest annual PM2.5 levels and prolonged periods of high air quality in winter. Patna emerges as the second most polluted city, while Mumbai and Chennai see an increase in annual pollution levels in 2025.
Published – 13 March 2026 21:32 IST
