POLLUTION METER
An analysis of air-quality monitoring data by CREA (Centre for Research on Energy and Clean Air) has revealed that the city accumulated enough particulate pollution by mid-Oct to breach India’s annual air-quality benchmark — 60 µg/m³ — even if its air were to remain completely free of PM10 for the rest of the year. Based on Central Pollution Control Board (CPCB) continuous monitoring data, Kolkata’s average PM10 concentration between Jan 1 and Oct 16 stood at 76 micrograms per cubic metre (µg/m³), up from 72 µg/m³ during the corresponding period in 2025, according to an analysis by CREA’s lead researcher Manoj Kumar . This represents an increase of nearly 6%, reversing the improvement observed over previous years. India’s National Ambient Air Quality Standards prescribe an annual PM10 limit of 60 µg/m³. The World Health Organization’s recommended annual guideline is considerably stricter, just 15 µg/m³. They calculated the cumulative PM10 concentration recorded since Jan 1 and divided it by 365 days. The date on which this figure reached 60 µg/m³ was identified as the point when a city’s annual pollution allowance had effectively been exhausted.
Kolkata’s average concentration during the study period was therefore more than five times the WHO guideline. Kolkata: Winter is yet to set in, but Kolkata has already exceeded its annual PM10 pollution level. The findings suggest that Kolkata is entering its most pollution-prone months with an already excessive burden of airborne particles, raising fresh concerns over the city’s deteriorating air quality. The CREA researchers adopted an unusual approach to illustrate the accumulated pollution burden.
This means Kolkata has entered the winter pollution season having already accumulated enough PM10 to push its full-year average to the national limit.