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 10 Jul 2025: Chile 44.2 µg/m³, Pakistan 33.7 µg/m³ and Peru 27.5 µg/m³.
- 1Chile47 cities44.2
- 2Pakistan11 cities33.7
- 3Peru5 cities27.5
- 4Japan563 cities22.8
- 5India214 cities20.4
- 6Mexico42 cities17.6
- 7South Korea140 cities14.1
- 8Martinique3 cities12.4
- 9Bosnia and Herzegovina5 cities11.6
- 10Malta5 cities10.6
- 11New Zealand10 cities10.6
- 12Hong Kong13 cities10.2
- 13Romania11 cities9.8
- 14Hungary11 cities9.5
- 15United States831 cities9.2
- 16Slovakia39 cities9.1
- 17Italy20 cities, was 98.6
- 18Spain120 cities, was 998.4
- 19Poland59 cities7.5
- 20Latvia4 cities7.3
+ 20 more countries, 7.2 µg/m³ and below
Not counted on this day, too few cities measured: Luxembourg since 10 Jul 2025, Greece since 7 Jul 2025, Czechia since 3 Jul 2025 and 5 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.