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 8 Jul 2025: Chile 48.5 µg/m³, Pakistan 37.6 µg/m³ and Peru 31.9 µg/m³.
- 1Chile47 cities48.5
- 2Pakistan11 cities37.6
- 3Peru5 cities31.9
- 4Japan564 cities22.2
- 5India211 cities19.2
- 6Mexico41 cities16.0
- 7South Korea140 cities14.4
- 8Bosnia and Herzegovina5 cities13.4
- 9Slovakia41 cities11.7
- 10Malta5 cities10.7
- 11New Zealand10 cities10.4
- 12Martinique3 cities10.3
- 13Italy23 cities, was 99.9
- 14Romania11 cities9.6
- 15Hong Kong13 cities9.5
- 16United States839 cities9.4
- 17Hungary11 cities9.0
- 18Spain117 cities, was 998.4
- 19Poland59 cities8.3
- 20Slovenia12 cities8.1
+ 21 more countries, 7.7 µg/m³ and below
Not counted on this day, too few cities measured: Greece since 7 Jul 2025, Czechia since 3 Jul 2025, Serbia 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.