SmogRank / World / South Korea / North Chungcheong / December 2025
Most polluted cities in North Chungcheong, South Korea, December 2025
7 cities in North Chungcheong, South Korea ranked by their average PM2.5 over the 31 days. Worst: Okcheon at 26.9 µg/m³, #341 of 2,960 cities in the world. Cleanest: Koesan at 19.9. A city needs measurements on 70% of the days to be ranked.
About 210K people in these 5 cities breathed unhealthy air on an average day of December 2025.
Ranked by people: each city's population times its share of unhealthy days, those with a daily mean over 35.4 µg/m³ (US AQI 101+). That is how many people living there breathed unhealthy air on an average day. Only cities measured at 2 or more places at least 3 km apart are ranked: one monitor shouldn't speak for a whole city. Population is the city itself, not its wider metro area.
- 1Cheongju-si 147K
- 2Chungju 41.9K
- 3Chinch'ŏn 12.2K
- 4Jungpyong 5.13K
- 5Koesan 4.3K
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
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SmogRank, most polluted cities in North Chungcheong, South Korea, PM2.5, December 2025, smogrank.com/kr/region/north-chungcheong/history/2025-12 (accessed 7 Oct 2026).
You're welcome to reuse a single chart, image or figure with this citation and a link. Terms. Raw monitor readings in bulk are published by OpenAQ, under each provider's licence.