Air quality in Kolkata
How bad is the air in Kolkata?
Kolkata’s 2025 average of AQI 99 is Satisfactory on the CPCB scale, and the median day was 72. 130 days crossed 100 (Moderate or worse) and 27 crossed 200 (Poor or worse).
The peak was AQI 291 on 12 December 2025. Fine particulate matter (PM2.5) set the index on 67% of days.
When Kolkata’s air is worst
December is the worst month at a mean of AQI 202; July the cleanest at ~48. That is the post-monsoon pattern: cooler nights lower the mixing height, winds drop, and whatever the city emits stays over it.
Plan around the profile, not the average: a purifier sized for December covers the rest of the year with headroom, and windows can be opened in July.
Pollution in Kolkata: what drives it
The main sources of air pollution in Kolkata, per its NCAP city action plan and CPCB source studies, are vehicle exhaust, coal and biomass burning, construction dust and winter inversion. CPCB bulletins name fine particulate matter (PM2.5) as the prominent pollutant on 67% of 2025's days.
- vehicle exhaust
- coal and biomass burning
- construction dust
- winter inversion
How Kolkata compares
Among the 62 cities we map, Kolkata has the 24th highest annual AQI, against a median of 94 across those cities.
Elsewhere in West Bengal, Siliguri averaged AQI 84.
See the full ranking on the India Air Quality Index by city.
Do you need an air purifier in Kolkata?
Verdict
For the worst months, yes — Kolkata is a seasonal case.
130 days in 2025 were Moderate or worse, concentrated around December. A single well-sized unit in the bedroom, run through those months, covers most of the exposure; the rest of the year it is optional unless someone at home has asthma or allergies.
What actually works
- Size by volume, not the box. Coverage claims assume ~2 air changes an hour; a December night wants 5.
- Bedroom first. Eight closed-door hours a night is where a purifier makes its measurable difference.
- Watch the live number. On Good and Satisfactory days, ventilate; on Poor days, close up and run the unit at the speed that delivers its CADR.
06 · The other half
Water in Kolkata
Groundwater near Kolkata averages ~896 mg/L TDS on CGWB monitoring — high on the BIS scale. The same government-data report, for what you drink.
Air
AQI 99
Satisfactory
Water
896 mg/L
TDS · High
Kolkata air — questions
What is the AQI in Kolkata today?
Today's figure comes from CPCB's live station feed and is shown at the top of this page, updated hourly when the feed is reachable. For context, Kolkata averaged AQI 99 across 2025 and peaked at 291 on 12 December 2025, so a single day's reading should be judged against that range.
How bad is air pollution in Kolkata?
Kolkata's 2025 average of AQI 99 sits in CPCB's "Satisfactory" band. 27 days were Poor, Very Poor or Severe, and 234 days were Good or Satisfactory, out of 364 bulletin days.
Which month has the worst air quality in Kolkata?
December, with a monthly average of AQI 202 in 2025. July was the cleanest at ~48. The post-monsoon build-up, cooler nights and a lower mixing height trap pollution from October onwards.
Is the air in Kolkata safe to breathe?
On average, yes: an annual AQI of 99 is within the "Satisfactory" band, where CPCB expects only minor discomfort for sensitive people. Individual days still crossed into Moderate or worse 130 times in 2025, so sensitive groups should watch the daily number.
Do I need an air purifier in Kolkata?
For the worst months, yes — Kolkata is a seasonal case. 130 days in 2025 were Moderate or worse, concentrated around December. A single well-sized unit in the bedroom, run through those months, covers most of the exposure; the rest of the year it is optional unless someone at home has asthma or allergies.
Where does Kolkata's air pollution come from?
The main sources of air pollution in Kolkata, per its NCAP city action plan and CPCB source studies, are vehicle exhaust, coal and biomass burning, construction dust and winter inversion. CPCB bulletins name fine particulate matter (PM2.5) as the prominent pollutant on 67% of 2025's days.
Where does this air quality data come from?
From the Central Pollution Control Board's daily AQI bulletin, published at 4 PM as a 24-hour average for each city with continuous monitoring stations. This page aggregates 364 bulletin days for Kolkata in 2025, drawn from 7 stations. The live figure uses the same CPCB station network through the Government of India's open-data feed.
Air quality in other cities
Data sources
- CPCB Daily AQI Bulletin (4 PM, 24-hour average), 2025 — city-level National AQI, prominent pollutant and station counts
- CPCB National Air Quality Index (2014) — six-band scale used for all categories
- NAAQS 2009 (24-hour PM2.5 60 µg/m³, PM10 100 µg/m³) — the concentrations that mark the Satisfactory/Moderate boundary
- Live readings: CPCB real-time station feed via data.gov.in, refreshed hourly.
Primary dataset: Central Pollution Control Board (CPCB) National Air Quality Index, Government of India.
Disclaimer: Figures are city-level averages of the CPCB daily AQI bulletin for the year shown and may differ from the air at your address, which depends on traffic, construction and the nearest station. This page is general information, not medical advice; for respiratory or cardiac conditions consult a qualified professional. Any purifier guidance is general sizing advice, not a product recommendation.