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 15 Dec 2025: Pakistan 225.6 µg/m³, India 64.1 µg/m³ and Bosnia and Herzegovina 41.2 µg/m³.
- 1Pakistan13 cities225.6
- 2India242 cities64.1
- 3Bosnia and Herzegovina5 cities41.2
- 4North Macedonia12 cities32.7
- 5Montenegro4 cities28.7
- 6Ghana4 cities26.2
- 7Peru4 cities24.4
- 8Thailand67 cities24.0
- 9Hong Kong13 cities23.4
- 10Mexico44 cities21.4
- 11Poland63 cities20.2
- 12South Korea139 cities18.5
- 13Chile44 cities16.6
- 14Bulgaria7 cities16.4
- 15Slovenia12 cities16.3
- 16Hungary12 cities, was 416.1
- 17Philippines3 cities15.7
- 18Taiwan45 cities15.3
- 19Slovakia9 cities12.7
- 20Austria38 cities11.8
+ 21 more countries, 11.3 µg/m³ and below
- 32United States831 cities7.2
Not counted on this day, too few cities measured: Ireland since 15 Dec 2025, Martinique since 2 Dec 2025, Kosovo since 30 Nov 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.