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 8 Jan 2026: Pakistan 203.5 µg/m³, India 63.1 µg/m³ and Montenegro 60.5 µg/m³.
- 1Pakistan12 cities203.5
- 2India242 cities63.1
- 3Montenegro5 cities60.5
- 4Bosnia and Herzegovina5 cities58.0
- 5North Macedonia13 cities50.8
- 6Ghana3 cities33.1
- 7Peru6 cities26.8
- 8Thailand74 cities23.7
- 9Hong Kong13 cities23.2
- 10Mexico51 cities22.7
- 11Romania16 cities21.7
- 12Poland60 cities21.5
- 13Laos3 cities18.2
- 14Slovenia12 cities18.2
- 15South Korea140 cities18.0
- 16Bulgaria7 cities17.2
- 17Chile42 cities17.0
- 18Hungary13 cities16.6
- 19Switzerland10 cities14.1
- 20Taiwan45 cities14.1
+ 24 more countries, 13.5 µg/m³ and below
- 35United States866 cities7.6
Not counted on this day, too few cities measured: Czechia since 7 Jan 2026, Philippines since 4 Jan 2026, Sweden since 17 Dec 2025 and 3 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.