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 10 Jun 2025: Chile 62.8 µg/m³, Pakistan 49.8 µg/m³ and India 31.3 µg/m³.
- 1Chile46 cities62.8
- 2Pakistan5 cities49.8
- 3India218 cities31.3
- 4Peru6 cities28.1
- 5Canada111 cities24.4
- 6Mexico40 cities18.2
- 7Thailand78 cities15.4
- 8South Korea139 cities15.3
- 9Serbia38 cities14.7
- 10Romania6 cities12.6
- 11Japan566 cities12.3
- 12Hungary4 cities, was 411.4
- 13Latvia3 cities9.8
- 14United States831 cities9.6
- 15New Zealand10 cities8.9
- 16Bulgaria5 cities8.6
- 17Lithuania4 cities8.4
- 18Poland72 cities8.1
- 19Hong Kong13 cities8.0
- 20Taiwan45 cities7.1
+ 5 more countries, 5.2 µg/m³ and below
Not counted on this day, too few cities measured: Austria since 9 Jun 2025, Bosnia and Herzegovina since 9 Jun 2025, Belgium since 9 Jun 2025 and 19 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.