Kolkata's Air Quality Shows Seasonal Pattern with Little Improvement Over Three Years
Kolkata's air quality continues to display a predictable seasonal pattern, characterized by temporary relief during monsoon months followed by severe deterioration in winter, with little sustained improvement observed over the past three years. This trend emerges from official data shared in Parliament and findings from a recent National Clean Air Programme (NCAP) study.
Parliamentary Discussion on Kolkata's Air Monitoring
The issue gained parliamentary attention when BJP MP from West Bengal, Samik Bhattacharya, sought details in the Rajya Sabha regarding whether the Central Pollution Control Board (CPCB) was monitoring Kolkata's Air Quality Index (AQI) and whether a source apportionment study had been conducted for the city. In a written reply, Union Minister of State for Environment, Kirti Vardhan Singh, confirmed that the CPCB, in coordination with the West Bengal Pollution Control Board (WBPCB), regularly monitors ambient air quality. He also stated that a source apportionment study for Kolkata was completed in 2025.
Consistent Pollution Trends Revealed by AQI Data
Average AQI data for the years 2023, 2024, and 2025 reveals a consistent pattern of high pollution levels during winter months, partial improvement during the monsoon season, and a steady rise in pollution from October onwards. January remains the most polluted month across all three years, with AQI levels reaching 225 in January 2023 and 2024, before showing a slight easing to 172 in January 2025.
Short-Lived Relief and Worsening Winter Pollution
While air quality does show improvement during the summer and monsoon months—particularly between June and September, when AQI levels often fall below 60—this relief proves to be short-lived. Pollution levels begin rising sharply in the post-monsoon period, typically peaking in November and December. In December 2025, the AQI surged to 202, marking the highest December reading recorded in the three-year period and indicating a concerning trend of worsening winter pollution.
The data underscores the persistent challenge of air pollution in Kolkata, highlighting the need for more effective and sustained interventions to break this cyclical pattern and achieve long-term air quality improvements for the city's residents.
