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 9 Oct 2025: Pakistan 53.0 µg/m³, India 27.2 µg/m³ and Peru 24.5 µg/m³.
- 1Pakistan11 cities53.0
- 2India213 cities27.2
- 3Peru5 cities24.5
- 4Philippines3 cities20.3
- 5Chile43 cities19.6
- 6Serbia35 cities16.5
- 7Poland72 cities15.0
- 8Taiwan45 cities13.8
- 9Hungary5 cities, was 1213.4
- 10Lithuania3 cities13.2
- 11Thailand75 cities12.4
- 12Bosnia and Herzegovina4 cities12.0
- 13Latvia4 cities10.7
- 14North Macedonia12 cities10.7
- 15Mexico52 cities10.5
- 16Slovakia31 cities10.1
- 17Switzerland10 cities9.7
- 18Australia22 cities9.2
- 19Hong Kong13 cities8.8
- 20Slovenia12 cities8.6
+ 21 more countries, 8.4 µg/m³ and below
- 28United States854 cities5.9
Not counted on this day, too few cities measured: Brazil since 9 Oct 2025, Ghana since 8 Oct 2025, Estonia since 5 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.