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 21 Jul 2025: Chile 45.2 µg/m³, Pakistan 37.7 µg/m³ and Peru 29.7 µg/m³.
- 1Chile47 cities45.2
- 2Pakistan11 cities37.7
- 3Peru6 cities29.7
- 4India222 cities21.5
- 5Philippines3 cities17.5
- 6New Zealand10 cities16.8
- 7Mexico51 cities14.6
- 8Malta5 cities12.2
- 9Canada117 cities11.8
- 10Greece10 cities11.7
- 11Italy24 cities, was 911.1
- 12Hong Kong13 cities11.0
- 13Norway20 cities10.6
- 14Poland60 cities10.2
- 15Iceland4 cities9.9
- 16Latvia4 cities9.5
- 17Lithuania4 cities9.3
- 18Martinique3 cities9.3
- 19Slovakia41 cities9.0
- 20Romania11 cities8.8
+ 22 more countries, 8.7 µg/m³ and below
- 29United States847 cities6.9
Not counted on this day, too few cities measured: Luxembourg since 10 Jul 2025, Czechia since 3 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.