SmogRank / World / South America / Chile / O'Higgins Region
Most polluted cities in O'Higgins Region, Chile
2 measured cities, last 7 days; 2 above the WHO 24-hour guideline. Worst: Rancagua at 25.4 µg/m³, #117 in the world.
India's National Air Quality Index (CPCB), PM2.5 sub-index. Show values as: µg/m³ · US AQI · India AQI · China AQI · European AQI · UK DAQI · Canada AQHI+. About the scales
Estimated: cities without a monitor
O'Higgins Region cities we can't measure, with model estimates for the last 7 days. Listed by population, not ranked: estimates aren't precise enough to rank. Model estimates from the Copernicus Atmosphere Monitoring Service (CAMS), adjusted to measured cities nearby where there are any. Adjusted, a single day lands within ×1.5 of what a monitor would read about two times in three; unadjusted, it can be off by half or double. Treat them as a guide, not a measurement.
| City | 7-day estimate |
|---|---|
| San Vicente de Tagua Tagua | ≈ 17 µg/m³ |
| Machalí | ≈ 37 µg/m³ |
| Santa Cruz | ≈ 19 µg/m³ |
| Chimbarongo | ≈ 19 µg/m³ |
| Graneros | ≈ 37 µg/m³ |
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SmogRank, most polluted cities in O'Higgins Region, Chile, PM2.5, last 7 days to 2 Oct 2026, 07:00 UTC, smogrank.com/cl/region/o-higgins-region?w=7d.
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Updated 2026-10-02 07:07 UTC. Values are PM2.5 (fine particles), the median of each city's monitors, as the India AQI PM2.5 sub-index.