Air quality in Chennai
How bad is the air in Chennai?
Chennai’s 2025 average of AQI 80 is Satisfactory on the CPCB scale, and the median day was 71. 71 days crossed 100 (Moderate or worse) and 0 crossed 200 (Poor or worse).
The peak was AQI 196 on 21 December 2025. Coarse dust (PM10) set the index on 88% of days.
When Chennai’s air is worst
December is the worst month at a mean of AQI 128; April the cleanest at ~56. 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 April.
Pollution in Chennai: what drives it
The main sources of air pollution in Chennai, per its NCAP city action plan and CPCB source studies, are vehicle exhaust, construction dust and port and industrial emissions. CPCB bulletins name coarse dust (PM10) as the prominent pollutant on 88% of 2025's days.
- vehicle exhaust
- construction dust
- port and industrial emissions
How Chennai compares
Among the 62 cities we map, Chennai has the 20th lowest annual AQI, against a median of 94 across those cities.
Elsewhere in Tamil Nadu, Coimbatore averaged AQI 70, Salem 65, Trichy 62 and Madurai 50.
See the full ranking on the India Air Quality Index by city.
Do you need an air purifier in Chennai?
Verdict
Not essential — Chennai's outdoor air stayed Satisfactory most of the year.
Only 71 of 364 bulletin days went above Satisfactory. Indoor sources (cooking, incense, dust, a busy road outside) can still justify a purifier for a nursery or an allergy household, and sizing still matters — see the calculator.
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 Chennai
Groundwater near Chennai averages ~780 mg/L TDS on CGWB monitoring — high on the BIS scale. The same government-data report, for what you drink.
Air
AQI 80
Satisfactory
Water
780 mg/L
TDS · High
Chennai air — questions
What is the AQI in Chennai 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, Chennai averaged AQI 80 across 2025 and peaked at 196 on 21 December 2025, so a single day's reading should be judged against that range.
How bad is air pollution in Chennai?
Chennai's 2025 average of AQI 80 sits in CPCB's "Satisfactory" band. 0 days were Poor, Very Poor or Severe, and 293 days were Good or Satisfactory, out of 364 bulletin days.
Which month has the worst air quality in Chennai?
December, with a monthly average of AQI 128 in 2025. April was the cleanest at ~56. The post-monsoon build-up, cooler nights and a lower mixing height trap pollution from October onwards.
Is the air in Chennai safe to breathe?
On average, yes: an annual AQI of 80 is within the "Satisfactory" band, where CPCB expects only minor discomfort for sensitive people. Individual days still crossed into Moderate or worse 71 times in 2025, so sensitive groups should watch the daily number.
Do I need an air purifier in Chennai?
Not essential — Chennai's outdoor air stayed Satisfactory most of the year. Only 71 of 364 bulletin days went above Satisfactory. Indoor sources (cooking, incense, dust, a busy road outside) can still justify a purifier for a nursery or an allergy household, and sizing still matters — see the calculator.
Where does Chennai's air pollution come from?
The main sources of air pollution in Chennai, per its NCAP city action plan and CPCB source studies, are vehicle exhaust, construction dust and port and industrial emissions. CPCB bulletins name coarse dust (PM10) as the prominent pollutant on 88% 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 Chennai in 2025, drawn from 9 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.