SmogRank / History / Country race
Countries, worst air first, day by day
Each country's typical measured city over the 30 days to every day since January 2023, worst first. Press Play to watch the order change, or drag the slider to any day.
The worst countries for PM2.5 over the 30 days to 16 Dec 2025: Pakistan 223.8 µg/m³, India 64.3 µg/m³ and Bosnia and Herzegovina 43.2 µg/m³.
- 1Pakistan13 cities223.8
- 2India243 cities64.3
- 3Bosnia and Herzegovina5 cities43.2
- 4North Macedonia12 cities33.6
- 5Montenegro4 cities32.3
- 6Ghana4 cities26.4
- 7Peru4 cities24.7
- 8Thailand67 cities23.9
- 9Hong Kong13 cities23.6
- 10Mexico45 cities21.4
- 11Poland63 cities20.6
- 12South Korea139 cities18.7
- 13Slovenia12 cities17.2
- 14Bulgaria7 cities17.1
- 15Chile42 cities17.0
- 16Philippines3 cities15.9
- 17Hungary12 cities, was 415.8
- 18Taiwan45 cities15.6
- 19Slovakia7 cities12.4
- 20Austria38 cities11.8
+ 21 more countries, the next at 11.6 µg/m³
- 32United States841 cities7.3
Not counted on this day, too few cities measured: Malta since 16 Dec 2025, Ireland since 15 Dec 2025, Martinique since 2 Dec 2025 and 6 more countries.
Countries counted each day
A country's number is its typical measured city: the median of its cities' means over the 30 days (a city needs 21 of them measured; 5 of 7 on the 7-day race), shown only with 3 such cities. A country whose monitors go quiet fades out where it stood rather than sliding down, so a gap never reads as cleaner air; "was" beside a city count marks a month after many cities joined or left. Some large countries are thin or missing because their monitors' licences don't allow reuse. How we rank.
Not covered: the government monitoring networks of China, Turkey and Iran, which publish only on their own websites. We are building the reader for China's network. The networks of Turkey and Iran don't answer requests from outside their countries, so we can't read them. Most cities there are missing from this board, not clean. Why.