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 24 Oct 2025: Pakistan 78.8 µg/m³, India 38.4 µg/m³ and Peru 26.1 µg/m³.
- 1Pakistan11 cities78.8
- 2India226 cities38.4
- 3Peru5 cities26.1
- 4Chile45 cities20.2
- 5Bosnia and Herzegovina5 cities18.4
- 6Philippines3 cities18.3
- 7North Macedonia12 cities14.6
- 8Mexico48 cities12.6
- 9Poland61 cities11.9
- 10Hungary5 cities, was 1211.8
- 11Romania9 cities11.6
- 12Latvia4 cities10.6
- 13Hong Kong13 cities9.7
- 14Switzerland10 cities8.4
- 15Montenegro5 cities8.4
- 16Slovenia12 cities8.4
- 17Kosovo6 cities8.4
- 18Slovakia18 cities8.3
- 19South Korea141 cities8.2
- 20Bulgaria5 cities8.1
+ 15 more countries, 8.1 µg/m³ and below
- 30United States873 cities5.7
Not counted on this day, too few cities measured: Brazil since 23 Oct 2025, France since 20 Oct 2025, Portugal since 20 Oct 2025 and 13 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 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.