SmogRank / World / Switzerland / December 2025

Most polluted cities in Switzerland, December 2025

6 cities in Switzerland ranked by their average PM2.5 over the 31 days. Worst: Winterthur at 22.6 µg/m³, #304 of 2,351 cities in the world. Cleanest: Lugano at 10.7. A city needs measurements on 70% of the days to be ranked.

← Winterthur 22.6
Every city in Switzerland ranked for December 2025, one column each, worst on the left and cleanest on the right. Point at it to read a city; tap to open it.
  1. 1Winterthurlow-cost sensorsZurich
    22.6
  2. 2BellinzonaTicino
    16.3
  3. 3BaselBasel-City
    13.6
  4. 4BernBern
    12.0
  5. 5ZürichZurich
    11.3
  6. 6LuganoTicino
    10.7
Good0–9.0
Moderate9.1–35.4
Sensitive groups35.5–55.4
Unhealthy55.5–125.4
Very unhealthy125.5–225.4
Hazardous225.5+

All cities in the world, December 2025 · Switzerland now

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SmogRank, most polluted cities in Switzerland, PM2.5, December 2025, smogrank.com/ch/history/2025-12 (accessed 2 Oct 2026).

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