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 12 Jun 2025: Chile 55.5 µg/m³, Pakistan 50.7 µg/m³ and India 32.7 µg/m³.
- 1Chile47 cities55.5
- 2Pakistan5 cities50.7
- 3India218 cities32.7
- 4Peru6 cities28.2
- 5Canada111 cities23.6
- 6Mexico42 cities17.9
- 7South Korea139 cities16.3
- 8Serbia38 cities15.9
- 9Thailand78 cities14.1
- 10Hungary4 cities, was 412.5
- 11Japan566 cities11.9
- 12Romania6 cities11.9
- 13Bulgaria5 cities9.5
- 14United States824 cities9.3
- 15Latvia3 cities8.9
- 16Lithuania4 cities8.4
- 17Taiwan45 cities8.1
- 18Poland72 cities7.7
- 19New Zealand10 cities7.3
- 20Hong Kong13 cities6.8
+ 5 more countries, 6.7 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.