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 13 Sep 2025: Pakistan 36.9 µg/m³, Chile 28.5 µg/m³ and Peru 26.3 µg/m³.
- 1Pakistan11 cities36.9
- 2Chile47 cities28.5
- 3Peru6 cities26.3
- 4Ghana4 cities24.1
- 5India221 cities19.5
- 6Philippines3 cities19.2
- 7Mexico40 cities12.4
- 8Malta5 cities11.3
- 9Japan558 cities10.3
- 10Italy23 cities9.8
- 11Bosnia and Herzegovina4 cities9.7
- 12Spain116 cities9.7
- 13Greece9 cities9.5
- 14Romania11 cities9.5
- 15Hungary11 cities, was 49.4
- 16Slovakia42 cities9.4
- 17New Zealand10 cities9.3
- 18Brazil3 cities9.2
- 19Poland64 cities9.1
- 20South Korea140 cities8.8
+ 23 more countries, 7.4 µg/m³ and below
- 25United States863 cities6.8
Not counted on this day, too few cities measured: Czechia since 8 Sep 2025, Lithuania since 5 Sep 2025 and Luxembourg since 2 Sep 2025.
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 and Turkey, which publish only on their own websites; we are building the readers for them. Most cities there are missing from this board, not clean. Why.