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 13 Nov 2025: Pakistan 143.6 µg/m³, India 50.2 µg/m³ and Bosnia and Herzegovina 30.0 µg/m³.
- 1Pakistan11 cities143.6
- 2India223 cities50.2
- 3Bosnia and Herzegovina5 cities30.0
- 4Peru6 cities28.5
- 5North Macedonia13 cities21.9
- 6Chile36 cities18.4
- 7Mexico49 cities18.0
- 8Poland59 cities15.9
- 9Hong Kong13 cities15.6
- 10Romania10 cities15.5
- 11South Korea141 cities13.5
- 12Hungary12 cities, was 1212.7
- 13Slovakia13 cities, was 4212.7
- 14Latvia4 cities12.3
- 15Slovenia11 cities11.5
- 16Bulgaria7 cities11.3
- 17Montenegro5 cities11.0
- 18Austria34 cities9.1
- 19Greece3 cities8.8
- 20Switzerland10 cities7.8
+ 18 more countries, 7.3 µg/m³ and below
- 30United States868 cities5.6
Not counted on this day, too few cities measured: Ghana since 13 Nov 2025, Philippines since 13 Nov 2025, Kosovo since 13 Nov 2025 and 10 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.