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 30 Dec 2024: Pakistan 236.0 µg/m³, India 107.3 µg/m³ and China 39.7 µg/m³.
- 1Pakistan3 cities236.0
- 2India5 cities107.3
- 3China4 cities39.7
- 4Hong Kong13 cities39.3
- 5Thailand16 cities35.6
- 6Poland72 cities30.4
- 7Slovenia12 cities30.1
- 8Mexico15 cities29.3
- 9Slovakia41 cities28.5
- 10Czechia39 cities27.8
- 11Hungary11 cities26.5
- 12Martinique3 cities20.5
- 13Croatia5 cities18.3
- 14South Korea141 cities17.7
- 15Chile45 cities17.6
- 16Bulgaria8 cities16.6
- 17Austria36 cities15.9
- 18Peru17 cities15.6
- 19Taiwan42 cities14.4
- 20The Netherlands36 cities13.6
+ 24 more countries, 13.3 µg/m³ and below
- 30United States827 cities7.5
Not counted on this day, too few cities measured: Serbia since 30 Dec 2024, Lithuania since 28 Dec 2024, Bosnia and Herzegovina since 27 Dec 2024 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.