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 28 Jul 2025: Pakistan 39.3 µg/m³, Chile 35.8 µg/m³ and Peru 29.3 µg/m³.
- 1Pakistan11 cities39.3
- 2Chile47 cities35.8
- 3Peru6 cities29.3
- 4New Zealand10 cities24.8
- 5Ghana3 cities22.9
- 6India207 cities18.7
- 7Philippines3 cities17.7
- 8Brazil3 cities16.0
- 9Hong Kong13 cities13.7
- 10Greece10 cities12.3
- 11Finland15 cities11.9
- 12South Korea128 cities11.8
- 13Malta4 cities11.0
- 14Romania11 cities11.0
- 15Mexico48 cities10.7
- 16Martinique3 cities10.4
- 17Canada112 cities9.2
- 18Bosnia and Herzegovina5 cities8.9
- 19Ireland4 cities, was 78.9
- 20Sweden16 cities8.9
+ 24 more countries, 8.5 µg/m³ and below
- 31United States825 cities7.4
Not counted on this day, too few cities measured: Lithuania since 25 Jul 2025, Iceland since 22 Jul 2025, Serbia since 3 Jul 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.