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 30 days to 19 Jul 2025: Chile 53.4 µg/m³, Pakistan 38.0 µg/m³ and Peru 27.7 µg/m³.
- 1Chile47 cities53.4
- 2Pakistan11 cities38.0
- 3Peru5 cities27.7
- 4India211 cities21.1
- 5New Zealand10 cities13.5
- 6Brazil41 cities13.3
- 7Mexico38 cities13.1
- 8Japan565 cities12.6
- 9South Korea140 cities11.8
- 10Italy23 cities, was 2011.7
- 11Martinique3 cities11.6
- 12Malta4 cities11.2
- 13Bosnia and Herzegovina5 cities10.2
- 14Slovakia41 cities9.9
- 15Spain115 cities, was 879.4
- 16Greece7 cities9.2
- 17Hungary11 cities, was 128.8
- 18Canada117 cities8.5
- 19Hong Kong13 cities8.4
- 20Romania11 cities8.2
+ 22 more countries, the next at 8.1 µg/m³
- 21United States840 cities8.1
Not counted on this day, too few cities measured: Serbia since 10 Jul 2025, Thailand since 10 Jul 2025, Taiwan since 10 Jul 2025 and Laos since 8 Jun 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, Turkey and Iran, which publish only on their own websites. We are building the reader for China's network. The networks of Turkey and Iran don't answer requests from outside their countries, so we can't read them. Most cities there are missing from this board, not clean. Why.