Kolkata vs Salem
Side-by-side air quality comparison between Kolkata and Salem.
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 | Salem |
|---|---|---|
| PM2.5(µg/m³) | 64.70 | 13.70 |
| PM10(µg/m³) | 69.40 | 16.40 |
| NO₂(µg/m³) | 18.10 | 15.30 |
| SO₂(µg/m³) | 13.10 | 9.30 |
| O₃(µg/m³) | 86.00 | 37.00 |
| CO(µg/m³) | 428.00 | 240.00 |
CPCB Multi-Year History (2016–2024)
Summary
Overview
In 2024, Kolkata averaged an AQI of 101 while Salem averaged 68 — a 33-point (49%) gap, with Kolkata the more polluted and Salem the cleaner of the two. On 208 days when both cities reported, Salem was cleaner on 181 of them; the average daily gap was 98 AQI points.
Seasonality & days
Kolkata peaks in January, while Salem peaks in April. Kolkata logged 1% Severe days and 47.800000000000004% Good-or-Satisfactory days; Salem was 0% Severe and 87.1% Good-or-Satisfactory. Longest clean-air streaks: Kolkata 75 days, Salem 17 days.
Year-over-year progress
Kolkata has improved by 76 AQI points (42.9%) from 2017 to 2024; Salem has improved by 5 AQI points (6.8%) over the same window. The worst recorded day for Kolkata reached AQI 453 at Rabindra Bharati University (WBPCB) on 2019-01-23; Salem hit AQI 214 at Sona College of Technology (TNPCB) on 2024-01-15.
Station-level disparity
Kolkata spans 7 CPCB stations with a 56-point spread (min 95, max 151); Salem spans 1 stations with a 0-point spread (min 73, max 73).
Verdict
🏆 Salem has better air quality with an AQI of 23 compared to Kolkata's 117. That's a significant difference of 94 points.