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 14 Jun 2025: Chile 52.4 µg/m³, Pakistan 46.8 µg/m³ and India 31.2 µg/m³.
- 1Chile47 cities52.4
- 2Pakistan5 cities46.8
- 3India218 cities31.2
- 4Peru6 cities26.8
- 5Mexico45 cities16.4
- 6South Korea139 cities15.6
- 7Serbia38 cities13.8
- 8Canada111 cities12.5
- 9Thailand78 cities12.1
- 10Hungary4 cities, was 410.8
- 11Japan565 cities10.5
- 12Bulgaria5 cities9.6
- 13United States828 cities9.6
- 14New Zealand10 cities9.2
- 15The Netherlands22 cities8.7
- 16Lithuania4 cities8.4
- 17United Kingdom64 cities8.2
- 18Poland72 cities8.2
- 19Taiwan45 cities7.2
- 20Hong Kong13 cities6.3
+ 4 more countries, 5.7 µg/m³ and below
Not counted on this day, too few cities measured: Latvia since 13 Jun 2025, Romania since 13 Jun 2025, Austria since 9 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.