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 9 Jun 2025: Chile 65.1 µg/m³, Pakistan 44.5 µg/m³ and India 31.3 µg/m³.
- 1Chile46 cities65.1
- 2Pakistan4 cities44.5
- 3India204 cities31.3
- 4Peru5 cities27.6
- 5Canada111 cities20.6
- 6Mexico41 cities17.2
- 7South Korea139 cities16.0
- 8Thailand78 cities15.3
- 9Serbia38 cities14.5
- 10Japan567 cities12.6
- 11Romania6 cities12.2
- 12Hungary4 cities, was 411.4
- 13New Zealand10 cities10.3
- 14Latvia3 cities10.2
- 15United States833 cities10.1
- 16Lithuania4 cities9.3
- 17Hong Kong13 cities8.8
- 18Poland73 cities8.6
- 19Bulgaria5 cities7.7
- 20Taiwan45 cities6.8
+ 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.