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 5 Jan 2026: Pakistan 209.8 µg/m³, India 63.0 µg/m³ and Montenegro 57.4 µg/m³.
- 1Pakistan12 cities209.8
- 2India244 cities63.0
- 3Montenegro5 cities57.4
- 4Bosnia and Herzegovina5 cities56.9
- 5North Macedonia12 cities48.2
- 6Ghana3 cities33.4
- 7Peru6 cities27.3
- 8Hong Kong13 cities24.0
- 9Thailand74 cities24.0
- 10Romania16 cities21.2
- 11Mexico50 cities21.0
- 12Poland62 cities19.8
- 13Czechia3 cities19.1
- 14South Korea140 cities19.0
- 15Slovenia12 cities18.7
- 16Laos3 cities18.4
- 17Hungary13 cities17.2
- 18Bulgaria7 cities17.1
- 19Chile42 cities17.1
- 20Switzerland10 cities13.2
+ 25 more countries, 13.2 µg/m³ and below
- 37United States868 cities7.3
Not counted on this day, too few cities measured: Philippines since 4 Jan 2026, Sweden since 17 Dec 2025, Malta since 16 Dec 2025 and 2 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.