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 4 Nov 2025: Pakistan 107.4 µg/m³, India 44.3 µg/m³ and Peru 28.2 µg/m³.
- 1Pakistan11 cities107.4
- 2India219 cities44.3
- 3Peru6 cities28.2
- 4Bosnia and Herzegovina5 cities22.3
- 5North Macedonia13 cities19.7
- 6Chile36 cities19.3
- 7Hong Kong13 cities14.9
- 8Mexico47 cities14.7
- 9Romania10 cities13.8
- 10Poland59 cities12.8
- 11Bulgaria7 cities12.2
- 12Kosovo7 cities11.2
- 13Slovakia10 cities, was 4211.1
- 14Latvia4 cities10.7
- 15Montenegro5 cities9.3
- 16South Korea141 cities9.2
- 17Hungary11 cities, was 129.1
- 18Australia23 cities7.6
- 19Martinique3 cities7.5
- 20Slovenia11 cities7.5
+ 16 more countries, 7.4 µg/m³ and below
- 29United States870 cities5.4
Not counted on this day, too few cities measured: Lithuania since 31 Oct 2025, Philippines since 25 Oct 2025, Brazil since 23 Oct 2025 and 12 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.