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 7 days to 11 Oct 2025: Pakistan 51.7 µg/m³, India 33.4 µg/m³ and Peru 25.3 µg/m³.
- 1Pakistan11 cities51.7
- 2India229 cities33.4
- 3Peru5 cities25.3
- 4Philippines3 cities21.5
- 5Chile45 cities19.5
- 6Serbia30 cities15.3
- 7Hungary5 cities, was 1214.7
- 8Bosnia and Herzegovina5 cities14.6
- 9North Macedonia13 cities13.6
- 10Taiwan45 cities13.5
- 11Thailand73 cities12.2
- 12Poland71 cities11.4
- 13Belgium47 cities11.1
- 14Lithuania3 cities10.2
- 15Hong Kong13 cities9.9
- 16Switzerland10 cities9.5
- 17Mexico51 cities9.2
- 18Martinique3 cities8.8
- 19Australia22 cities8.6
- 20Romania9 cities8.5
+ 21 more countries, 8.3 µg/m³ and below
- 36United States858 cities5.2
Not counted on this day, too few cities measured: Ireland since 10 Oct 2025, Brazil since 9 Oct 2025, Ghana since 8 Oct 2025 and 7 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.