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 Aug 2025: Chile 38.1 µg/m³, Pakistan 36.4 µg/m³ and Peru 28.2 µg/m³.
- 1Chile48 cities38.1
- 2Pakistan11 cities36.4
- 3Peru4 cities28.2
- 4Ghana3 cities25.6
- 5India230 cities23.7
- 6Philippines3 cities23.2
- 7Italy28 cities14.3
- 8Brazil3 cities12.7
- 9Bosnia and Herzegovina4 cities12.3
- 10Spain113 cities12.3
- 11Mexico42 cities12.0
- 12South Korea140 cities11.4
- 13Slovakia41 cities10.8
- 14Czechia18 cities10.1
- 15Switzerland11 cities10.0
- 16Greece9 cities9.9
- 17New Zealand10 cities9.9
- 18Japan560 cities9.6
- 19Romania11 cities9.6
- 20Hungary12 cities, was 49.3
+ 25 more countries, 9.1 µg/m³ and below
- 24United States853 cities8.8
Not counted on this day, too few cities measured: Martinique since 9 Aug 2025, China since 7 Aug 2025, Serbia since 3 Jul 2025 and 2 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.