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 18 Jul 2025: Chile 43.0 µg/m³, Pakistan 33.7 µg/m³ and Peru 31.0 µg/m³.
- 1Chile47 cities43.0
- 2Pakistan11 cities33.7
- 3Peru5 cities31.0
- 4India217 cities21.1
- 5Mexico49 cities15.5
- 6Philippines3 cities15.4
- 7New Zealand10 cities14.0
- 8Canada115 cities12.5
- 9Martinique3 cities11.0
- 10Hong Kong13 cities10.8
- 11Italy21 cities, was 910.8
- 12Finland15 cities10.1
- 13Malta5 cities10.1
- 14Greece9 cities9.9
- 15South Korea140 cities9.8
- 16Romania11 cities9.3
- 17Norway20 cities9.2
- 18Spain95 cities8.9
- 19Lithuania4 cities8.5
- 20Sweden15 cities8.5
+ 21 more countries, 8.4 µg/m³ and below
- 27United States847 cities7.2
Not counted on this day, too few cities measured: Ireland since 14 Jul 2025, Luxembourg since 10 Jul 2025, Czechia since 3 Jul 2025 and 4 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.