Siwan — Pollution Health Impact
809 days of CPCB data (2021–2024), translated through WHO 2021, Berkeley Earth and EPIC AQLI methods. Based on CPCB station data, 2016–present.
Bihar · Live Siwan AQI →
Living in Siwan is the population-level health-equivalent of smoking 4.7 cigarettes a day — roughly 1,708 cigarettes a year. On average, that chronic exposure shortens life expectancy by about 9.6 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 Siwan meet?
24-hour PM2.5 compliance vs WHO 2021 targets.
- AQG0 days (0.0%)
- IT-45 days (0.6%)
- IT-339 days (4.8%)
- IT-244 days (5.4%)
- IT-1262 days (32.4%)
- Above IT-1459 days (56.7%)
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 Siwan's 9.6 year estimate.
- Heart + stroke: 6.5y
- COPD: 1.3y
- Child ALRI: 1.3y
- Lung cancer: 0.4y
Worst and best months
Drill into full monthly pattern on the seasonal Siwan page →
High-risk days for vulnerable residents
- Days above WHO IT-3 (37.5 µg/m³) — pregnancy & infant risk elevated
- 765 (94.6%)
- Days above WHO IT-1 (75 µg/m³) — high risk for children under 5
- 459 (56.7%)
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 Siwan compares to nearby cities
- Similar exposureDarbhanga5.1 cigs/day · 10.4 y lost · +0.4 vs Siwan
- Similar exposureMuzaffarpur4.7 cigs/day · 9.7 y lost · +0.1 vs Siwan
- Cleaner peerMeerut4.4 cigs/day · 9.1 y lost · -0.2 vs Siwan
- Dirtier peerMuzaffarpur4.7 cigs/day · 9.7 y lost · +0.1 vs Siwan
What the numbers say
Overview
Across 809 days of CPCB monitoring, the average adult in Siwan has breathed air with the health-equivalent of smoking 4.7 cigarettes a day — roughly 1,708 cigarettes every year (Berkeley Earth, 2015).
The data story
Using the Air Quality Life Index coefficient from EPIC at the University of Chicago, that long-run exposure reduces average life expectancy by roughly 9.6 years per resident. Of the 809 days on record, only 0 (0.0%) met the WHO 24-hour guideline of 15 µg/m³, while 459 days (56.7%) were above the loosest WHO Interim Target-1 (75 µg/m³).
Why this pattern
Seasonality matters: January is Siwan's worst month (7.3 cigs/day equivalent) and August is the best (2.2 cigs/day). Per WHO's 2024 attribution, 68% of PM2.5-attributable deaths globally come from ischaemic heart disease and stroke, 14% from COPD, 14% from acute lower-respiratory infections in children under 5, and 4% from lung cancer.
What to do with this
These numbers are communication heuristics, not a clinical diagnosis — but they make the stakes legible. Low-cost actions stack: check 24-hour PM2.5 daily, wear an N95 in winter mornings, and run a HEPA purifier indoors during peak months. Pregnant residents and children under 5 are most at risk (WHO 2024) and benefit most from clean-air interventions on the 765 days (94.6%) when PM2.5 sits above WHO IT-3 (37.5 µg/m³).