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 30 days to 26 Oct 2025: Pakistan 83.5 µg/m³, India 39.5 µg/m³ and Peru 25.2 µg/m³.
- 1Pakistan11 cities83.5
- 2India221 cities39.5
- 3Peru5 cities25.2
- 4Chile43 cities20.2
- 5Bosnia and Herzegovina5 cities19.0
- 6North Macedonia12 cities15.0
- 7Mexico48 cities13.0
- 8Poland59 cities12.4
- 9Romania8 cities12.1
- 10Hungary5 cities, was 1211.9
- 11Hong Kong13 cities10.6
- 12Latvia4 cities10.6
- 13Slovakia19 cities8.8
- 14Slovenia12 cities8.7
- 15Kosovo4 cities8.7
- 16South Korea141 cities8.5
- 17Bulgaria5 cities8.4
- 18Switzerland10 cities8.3
- 19Montenegro5 cities8.3
- 20Lithuania3 cities8.1
+ 14 more countries, 7.7 µg/m³ and below
- 29United States873 cities5.7
Not counted on this day, too few cities measured: Philippines since 25 Oct 2025, Brazil since 23 Oct 2025, France since 20 Oct 2025 and 14 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.