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 7 days to 12 Dec 2025: Pakistan 234.4 µg/m³, India 59.8 µg/m³ and Bosnia and Herzegovina 39.8 µg/m³.
- 1Pakistan13 cities234.4
- 2India245 cities59.8
- 3Bosnia and Herzegovina5 cities39.8
- 4North Macedonia13 cities37.3
- 5Ghana3 cities31.0
- 6Montenegro5 cities29.8
- 7Hong Kong13 cities28.1
- 8Peru6 cities24.9
- 9Thailand72 cities24.1
- 10South Korea138 cities21.1
- 11Mexico52 cities20.2
- 12Slovenia12 cities, was 1220.2
- 13Hungary12 cities19.6
- 14Poland68 cities19.3
- 15Laos3 cities18.8
- 16Romania17 cities18.3
- 17Bulgaria7 cities18.1
- 18Chile45 cities17.2
- 19Slovakia17 cities, was 3315.2
- 20Taiwan45 cities13.9
+ 25 more countries, 12.4 µg/m³ and below
- 30United States851 cities, was 8697.8
Not counted on this day, too few cities measured: Ireland since 11 Dec 2025, Philippines since 10 Dec 2025, Serbia since 4 Dec 2025 and 4 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.