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 6 Nov 2025: Pakistan 145.8 µg/m³, India 40.2 µg/m³ and Peru 29.5 µg/m³.
- 1Pakistan11 cities145.8
- 2India213 cities40.2
- 3Peru6 cities29.5
- 4Bosnia and Herzegovina5 cities28.6
- 5North Macedonia13 cities26.3
- 6Chile39 cities18.5
- 7Ghana3 cities18.5
- 8Poland64 cities18.3
- 9Philippines3 cities18.0
- 10Romania10 cities18.0
- 11South Korea141 cities17.8
- 12Mexico54 cities17.6
- 13Hong Kong13 cities17.2
- 14Bulgaria7 cities13.9
- 15Slovakia32 cities12.1
- 16Kosovo8 cities11.9
- 17Hungary10 cities10.9
- 18Montenegro5 cities10.5
- 19Austria35 cities9.8
- 20Greece7 cities9.8
+ 23 more countries, 9.6 µg/m³ and below
- 30United States855 cities6.2
Not counted on this day, too few cities measured: Czechia since 6 Nov 2025, Lithuania since 29 Oct 2025, Italy since 28 Oct 2025 and 5 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.