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 5 Oct 2025: Pakistan 73.0 µg/m³, Peru 28.3 µg/m³ and Philippines 25.0 µg/m³.
- 1Pakistan11 cities73.0
- 2Peru5 cities28.3
- 3Philippines3 cities25.0
- 4India215 cities22.1
- 5Chile45 cities20.7
- 6Serbia34 cities17.9
- 7Ghana4 cities15.7
- 8Taiwan45 cities13.9
- 9Poland73 cities13.2
- 10Mexico50 cities12.4
- 11South Korea141 cities11.6
- 12Thailand75 cities11.2
- 13Bosnia and Herzegovina4 cities10.9
- 14Latvia4 cities10.6
- 15Romania7 cities9.8
- 16Lithuania3 cities9.3
- 17Brazil3 cities9.0
- 18The Netherlands35 cities9.0
- 19North Macedonia11 cities8.6
- 20Switzerland10 cities8.3
+ 21 more countries, 8.3 µg/m³ and below
- 31United States859 cities6.4
Not counted on this day, too few cities measured: Estonia since 5 Oct 2025, France since 5 Oct 2025, Ireland since 5 Oct 2025 and 8 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.