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 18 Nov 2025: Pakistan 150.3 µg/m³, India 53.4 µg/m³ and Bosnia and Herzegovina 33.4 µg/m³.
- 1Pakistan11 cities150.3
- 2India220 cities53.4
- 3Bosnia and Herzegovina5 cities33.4
- 4Peru6 cities29.4
- 5North Macedonia13 cities26.0
- 6Mexico48 cities19.3
- 7Ghana3 cities18.9
- 8Chile36 cities18.0
- 9Hong Kong13 cities16.5
- 10Romania9 cities15.9
- 11Poland62 cities15.8
- 12South Korea141 cities15.1
- 13Slovakia35 cities, was 4213.8
- 14Hungary12 cities13.7
- 15Bulgaria7 cities13.5
- 16Kosovo8 cities13.4
- 17Montenegro5 cities12.7
- 18Slovenia12 cities11.9
- 19Latvia4 cities11.6
- 20Czechia7 cities11.3
+ 22 more countries, 9.6 µg/m³ and below
- 34United States826 cities5.7
Not counted on this day, too few cities measured: Philippines since 13 Nov 2025, Lithuania since 31 Oct 2025, Brazil since 23 Oct 2025 and 6 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.