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 16 Nov 2025: Pakistan 149.9 µg/m³, India 51.7 µg/m³ and Bosnia and Herzegovina 34.3 µg/m³.
- 1Pakistan11 cities149.9
- 2India224 cities51.7
- 3Bosnia and Herzegovina5 cities34.3
- 4Peru6 cities29.2
- 5North Macedonia13 cities24.8
- 6Mexico48 cities18.7
- 7Chile36 cities18.4
- 8Hong Kong13 cities16.2
- 9Poland59 cities15.8
- 10Romania10 cities15.5
- 11South Korea141 cities14.8
- 12Slovakia33 cities, was 4213.9
- 13Hungary12 cities13.5
- 14Kosovo8 cities13.2
- 15Bulgaria7 cities13.1
- 16Montenegro5 cities12.6
- 17Slovenia12 cities12.4
- 18Latvia4 cities12.1
- 19Brazil41 cities10.5
- 20Austria37 cities9.7
+ 21 more countries, the next at 8.2 µg/m³
- 33United States847 cities5.7
Not counted on this day, too few cities measured: Ghana since 13 Nov 2025, Philippines since 13 Nov 2025, Lithuania since 31 Oct 2025 and 7 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, Turkey and Iran, which publish only on their own websites. We are building the reader for China's network. The networks of Turkey and Iran don't answer requests from outside their countries, so we can't read them. Most cities there are missing from this board, not clean. Why.