Kolkata — Pollution Health Impact
2,076 days of CPCB data (2017–2024), translated through WHO 2021, Berkeley Earth and EPIC AQLI methods. Based on CPCB station data, 2016–present.
West Bengal · Live Kolkata AQI →
Living in Kolkata is the population-level health-equivalent of smoking 3.5 cigarettes a day — roughly 1,265 cigarettes a year. On average, that chronic exposure shortens life expectancy by about 7.0 years per resident.
Cigarette-equivalence (Berkeley Earth 2015) and life-years lost (EPIC AQLI) are peer-reviewed communication heuristics, not clinical diagnoses. Full sources linked on the methodology page.
Headline impact numbers
Cigarettes/day by year
Annual average cigarette-equivalent.
Clean-air days (NAQI ≤ 50) by year
Days when NAQI stayed in the “Good” band.
Which WHO tier did Kolkata meet?
24-hour PM2.5 compliance vs WHO 2021 targets.
- AQG2 days (0.1%)
- IT-462 days (3.0%)
- IT-3435 days (21.0%)
- IT-2296 days (14.3%)
- IT-1466 days (22.4%)
- Above IT-1815 days (39.3%)
WHO AQG (15) · IT-4 (25) · IT-3 (37.5) · IT-2 (50) · IT-1 (75) µg/m³ (24-hour PM2.5).
Life-years lost, by disease
Applying WHO's global attribution (68/14/14/4) to Kolkata's 7.0 year estimate.
- Heart + stroke: 4.7y
- COPD: 1.0y
- Child ALRI: 1.0y
- Lung cancer: 0.3y
Worst and best months
Drill into full monthly pattern on the seasonal Kolkata page →
High-risk days for vulnerable residents
- Days above WHO IT-3 (37.5 µg/m³) — pregnancy & infant risk elevated
- 1,577 (76.0%)
- Days above WHO IT-1 (75 µg/m³) — high risk for children under 5
- 815 (39.3%)
Source: WHO 2021 AQG interim-target risk framework; WHO 2024 ambient-air fact sheet identifies children under 5 and pregnant residents as the most vulnerable groups.
How Kolkata compares to nearby cities
- Similar exposureAraria3.8 cigs/day · 7.7 y lost · +0.3 vs Kolkata
- Similar exposureJodhpur3.7 cigs/day · 7.5 y lost · +0.2 vs Kolkata
- Cleaner peerKishanganj3.4 cigs/day · 6.9 y lost · -0.0 vs Kolkata
- Dirtier peerGwalior3.5 cigs/day · 7.0 y lost · +0.0 vs Kolkata
What the numbers say
Overview
Across 2,076 days of CPCB monitoring, the average adult in Kolkata has breathed air with the health-equivalent of smoking 3.5 cigarettes a day — roughly 1,265 cigarettes every year (Berkeley Earth, 2015).
The data story
EPIC's AQLI research attributes about 7.0 life-years lost per person from this chronic exposure. The WHO Air Quality Guideline was met on just 2 of 2,076 days (0.1%); 815 days (39.3%) exceeded even the 75 µg/m³ Interim Target-1 threshold.
Why this pattern
The burden concentrates in January — when the average cigarette-equivalent climbs to 6.8/day — and eases in July (1.7/day). Globally, WHO attributes 68% of PM2.5 deaths to heart disease and stroke, with the remainder split across COPD, childhood ALRI, and lung cancer.
What to do with this
Cigarette-equivalence is a communication tool, not a medical verdict. Still, the direction is clear: time indoors with a HEPA unit and a good-fit mask outdoors during the 1,577 days (76.0%) above WHO IT-3 meaningfully lowers exposure — especially for pregnant residents and children under 5.