Kolkata vs Siwan
Side-by-side air quality comparison between Kolkata and Siwan.
Live AQI from Open-Meteo CAMS (~45 km global model, updated hourly). Multi-year history from CPCB station data via aqinow.co pipeline (2016–2024, station-level daily records).
AQI Comparison
Pollutant-level comparison (PM2.5, PM10, O3, NO2, SO2, CO)▾
| Pollutant | Kolkata | Siwan |
|---|---|---|
| PM2.5(µg/m³) | 71.70 | 108.00 |
| PM10(µg/m³) | 75.70 | 122.50 |
| NO₂(µg/m³) | 22.30 | 59.80 |
| SO₂(µg/m³) | 12.00 | 14.10 |
| O₃(µg/m³) | 60.00 | 4.00 |
| CO(µg/m³) | 392.00 | 856.00 |
CPCB Multi-Year History (2016–2024)
Summary
Overview
In 2024, Kolkata averaged an AQI of 101 while Siwan averaged 148 — a 47-point (47%) gap, with Siwan the more polluted and Kolkata the cleaner of the two. On 491 days when both cities reported, Kolkata was cleaner on 339 of them; the average daily gap was 76 AQI points.
Seasonality & days
Both cities see their worst air in January on average. Kolkata logged 1% Severe days and 47.800000000000004% Good-or-Satisfactory days; Siwan was 5.2% Severe and 17.7% Good-or-Satisfactory. Longest clean-air streaks: Kolkata 75 days, Siwan 13 days.
Year-over-year progress
Kolkata has improved by 76 AQI points (42.9%) from 2017 to 2024; Siwan has improved by 184 AQI points (55.4%) over the same window. The worst recorded day for Kolkata reached AQI 453 at Rabindra Bharati University (WBPCB) on 2019-01-23; Siwan hit AQI 488 at Chitragupta Nagar (BSPCB) on 2022-12-30.
Station-level disparity
Kolkata spans 7 CPCB stations with a 56-point spread (min 95, max 151); Siwan spans 1 stations with a 0-point spread (min 197, max 197).
Verdict
🏆 Kolkata has better air quality with an AQI of 140 compared to Siwan's 260. That's a significant difference of 120 points.