SmogRank / Countries / Slovenia / October 2025

Most polluted cities in Slovenia, October 2025

7 cities in Slovenia ranked by their average PM2.5 over the 31 days. Worst: Novo Mesto at 9.9 µg/m³, #404 of 2,110 cities in the world. Cleanest: Koper at 5.1. A city needs measurements on 70% of the days to be ranked.

  1. 1Novo MestoUrban Municipality of Novo Mesto
    9.9
  2. 2LjubljanaLjubljana
    8.7
  3. 3CeljeUrban Municipality of Celje
    8.6
  4. 4PtujUrban Municipality of Ptuj
    8.0
  5. 5TrbovljeMunicipality of Trbovlje
    7.7
  6. 6MariborUrban Municipality of Maribor
    7.3
  7. 7KoperUrban Municipality of Koper
    5.1
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, October 2025 · Slovenia now