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 Oct 2025: Pakistan 62.3 µg/m³, Peru 30.9 µg/m³ and India 26.3 µg/m³.
- 1Pakistan11 cities62.3
- 2Peru5 cities30.9
- 3India215 cities26.3
- 4Chile46 cities21.8
- 5Philippines3 cities18.6
- 6Ghana4 cities17.8
- 7Serbia35 cities12.8
- 8Bosnia and Herzegovina5 cities12.6
- 9Taiwan45 cities11.4
- 10North Macedonia9 cities11.2
- 11Mexico48 cities10.8
- 12Thailand73 cities10.5
- 13Poland71 cities9.5
- 14Brazil3 cities8.9
- 15Hungary7 cities8.8
- 16Italy6 cities, was 278.8
- 17Hong Kong13 cities8.0
- 18South Korea141 cities8.0
- 19Latvia4 cities8.0
- 20Spain105 cities7.9
+ 25 more countries, 7.9 µg/m³ and below
- 34United States875 cities6.5
Not counted on this day, too few cities measured: Ireland since 13 Oct 2025, Estonia since 12 Oct 2025, Luxembourg since 10 Oct 2025 and 3 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.