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 16 Feb 2025: India 90.0 µg/m³, Pakistan 80.8 µg/m³ and Bosnia and Herzegovina 74.5 µg/m³.
- 1India5 cities90.0
- 2Pakistan4 cities80.8
- 3Bosnia and Herzegovina3 cities74.5
- 4Thailand63 cities, was 1645.6
- 5China4 cities38.9
- 6Serbia15 cities36.5
- 7Poland74 cities28.6
- 8Slovenia12 cities28.5
- 9Romania9 cities27.2
- 10Bulgaria5 cities26.1
- 11South Korea141 cities22.9
- 12Hungary10 cities22.0
- 13Slovakia42 cities20.6
- 14Croatia3 cities19.7
- 15The Netherlands23 cities19.7
- 16Chile45 cities19.6
- 17Belgium45 cities19.4
- 18Hong Kong13 cities19.3
- 19Austria36 cities17.9
- 20Peru4 cities17.6
+ 23 more countries, 17.1 µg/m³ and below
- 35United States821 cities7.2
Not counted on this day, too few cities measured: Luxembourg since 2 Feb 2025, Czechia since 18 Jan 2025, Singapore since 16 Jan 2025 and Lithuania since 1 Jan 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.