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 20 Aug 2025: Pakistan 38.3 µg/m³, Chile 30.7 µg/m³ and Peru 24.2 µg/m³.
- 1Pakistan11 cities38.3
- 2Chile47 cities30.7
- 3Peru6 cities24.2
- 4Philippines3 cities20.0
- 5Ghana4 cities19.6
- 6India231 cities18.3
- 7Spain88 cities17.5
- 8Malta5 cities16.8
- 9Italy28 cities14.5
- 10Switzerland11 cities14.3
- 11Czechia33 cities14.2
- 12Mexico39 cities13.5
- 13Slovakia42 cities13.5
- 14New Zealand10 cities13.3
- 15Bosnia and Herzegovina4 cities12.5
- 16Slovenia12 cities11.4
- 17Hungary12 cities11.0
- 18Luxembourg3 cities11.0
- 19France106 cities, was 10410.8
- 20Austria36 cities10.7
+ 26 more countries, 10.6 µg/m³ and below
- 35United States856 cities7.1
Not counted on this day, too few cities measured: China since 7 Aug 2025, Serbia since 3 Jul 2025, Thailand since 3 Jul 2025 and Taiwan since 3 Jul 2025.
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.