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 18 Jun 2025: Pakistan 50.0 µg/m³, Chile 32.9 µg/m³ and India 25.7 µg/m³.
- 1Pakistan5 cities50.0
- 2Chile43 cities32.9
- 3India217 cities25.7
- 4Peru6 cities23.4
- 5New Zealand10 cities16.4
- 6South Korea140 cities16.0
- 7Mexico41 cities11.8
- 8Serbia38 cities11.4
- 9Thailand75 cities10.3
- 10Bulgaria5 cities9.7
- 11Japan559 cities9.5
- 12Hungary4 cities, was 49.4
- 13Poland72 cities9.0
- 14The Netherlands22 cities8.6
- 15Lithuania4 cities8.3
- 16Hong Kong13 cities8.2
- 17United States823 cities8.1
- 18Austria37 cities7.9
- 19United Kingdom66 cities7.4
- 20Canada116 cities7.1
+ 4 more countries, 6.8 µg/m³ and below
Not counted on this day, too few cities measured: Spain since 17 Jun 2025, Latvia since 17 Jun 2025, Romania since 17 Jun 2025 and 20 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.