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 7 Jul 2025: Chile 52.6 µg/m³, Pakistan 45.5 µg/m³ and Peru 26.1 µg/m³.
- 1Chile46 cities52.6
- 2Pakistan6 cities45.5
- 3Peru6 cities26.1
- 4India202 cities23.7
- 5Italy7 cities, was 2014.5
- 6Bosnia and Herzegovina5 cities14.1
- 7South Korea140 cities14.0
- 8New Zealand10 cities14.0
- 9Japan565 cities12.4
- 10Spain51 cities, was 8712.3
- 11Serbia32 cities12.3
- 12Mexico34 cities11.9
- 13Slovakia31 cities11.5
- 14Slovenia12 cities11.0
- 15Thailand71 cities11.0
- 16Hungary4 cities, was 1210.4
- 17Romania8 cities9.2
- 18France14 cities9.1
- 19United States838 cities8.9
- 20Canada117 cities8.2
+ 17 more countries, 8.0 µg/m³ and below
Not counted on this day, too few cities measured: Switzerland since 17 Jun 2025, Malta since 14 Jun 2025, Portugal since 12 Jun 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.