SmogRank / World / Japan / Okayama / September 2025

Most polluted cities in Okayama, Japan, September 2025

12 cities in Okayama, Japan ranked by their average PM2.5 over the 30 days. Worst: Bizen at 10.1 µg/m³, #631 of 3,052 cities in the world. Cleanest: Niimi at 5.3. A city needs measurements on 70% of the days to be ranked.

Ranked by unhealthy days: the share of each city's measured days with a daily mean over 35.4 µg/m³ (US AQI 101+), Unhealthy for Sensitive Groups or worse on the US EPA's scale. Ties go to the higher average.

← Bizen 0% 0.75%0
Every city in Okayama, Japan ranked for September 2025, one column each, ranked by unhealthy days: height is the share of its measured days that were unhealthy, colour its average. Point at it to read a city; tap to open it.
  1. 1Bizen
    0%
  2. 2Tamano
    0%
  3. 3Hayashima
    0%
  4. 4Okayama
    0%
  5. 4Kurashiki
    0%
  6. 6Kasaoka
    0%
  7. 7Shimogamo
    0%
  8. 8Tsuyama
    0%
  9. 8Sōja
    0%
  10. 10Asakuchi
    0%
  11. 11Takahashi
    0%
  12. 12Niimi
    0%
Good0–50
Moderate51–100
Sensitive groups101–150
Unhealthy151–200
Very unhealthy201–300
Hazardous301+

The US EPA's Air Quality Index for PM2.5 (2024 breakpoints). Show values as: µg/m³ · US AQI · India AQI · China AQI · European AQI · UK DAQI · Canada AQHI+. About the scales

All cities in the world, September 2025 · All cities in Japan, September 2025 · Okayama now

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SmogRank, most polluted cities in Okayama, Japan, PM2.5, September 2025, smogrank.com/jp/region/okayama/history/2025-09 (accessed 6 Oct 2026).

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