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 3 Jan 2026: Pakistan 214.0 µg/m³, India 63.0 µg/m³ and Bosnia and Herzegovina 57.0 µg/m³.
- 1Pakistan12 cities214.0
- 2India242 cities63.0
- 3Bosnia and Herzegovina5 cities57.0
- 4Montenegro5 cities55.0
- 5North Macedonia12 cities48.1
- 6Ghana3 cities33.7
- 7Peru6 cities27.3
- 8Hong Kong13 cities24.6
- 9Thailand74 cities24.1
- 10Mexico49 cities20.8
- 11Romania16 cities20.7
- 12Poland62 cities20.5
- 13Czechia3 cities19.4
- 14Slovenia12 cities19.0
- 15Laos3 cities18.4
- 16South Korea140 cities18.3
- 17Chile43 cities17.1
- 18Hungary13 cities17.1
- 19Bulgaria7 cities17.0
- 20Slovakia11 cities, was 1414.1
+ 26 more countries, 13.9 µg/m³ and below
- 38United States868 cities7.3
Not counted on this day, too few cities measured: Sweden since 17 Dec 2025, Malta since 16 Dec 2025, Martinique since 2 Dec 2025 and Kosovo since 30 Nov 2025.
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.