Chennai vs Salem
Side-by-side air quality comparison between Chennai 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
CPCB Multi-Year History (2016–2024)
Summary
Overview
In 2024, Chennai averaged an AQI of 68 while Salem averaged 68 — a 0-point (0%) gap, with Salem the more polluted and Chennai the cleaner of the two. On 208 days when both cities reported, Salem was cleaner on 179 of them; the average daily gap was 49 AQI points.
Seasonality & days
Chennai peaks in December, while Salem peaks in April. Chennai logged 0% Severe days and 57.5% Good-or-Satisfactory days; Salem was 0% Severe and 87.1% Good-or-Satisfactory. Longest clean-air streaks: Chennai 53 days, Salem 17 days.
Year-over-year progress
Chennai has improved by 25 AQI points (26.9%) from 2017 to 2024; Salem has improved by 5 AQI points (6.8%) over the same window. The worst recorded day for Chennai reached AQI 391 at Kodungaiyur (TNPCB) on 2021-05-14; Salem hit AQI 214 at Sona College of Technology (TNPCB) on 2024-01-15.
Station-level disparity
Chennai spans 9 CPCB stations with a 27-point spread (min 63, max 90); Salem spans 1 stations with a 0-point spread (min 73, max 73).