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 19 Dec 2024: Pakistan 200.7 µg/m³, India 126.3 µg/m³ and Bosnia and Herzegovina 102.6 µg/m³.
- 1Pakistan3 cities200.7
- 2India4 cities126.3
- 3Bosnia and Herzegovina3 cities102.6
- 4Serbia25 cities57.5
- 5China4 cities30.6
- 6Slovenia12 cities30.5
- 7Hong Kong13 cities27.4
- 8Croatia6 cities24.8
- 9Thailand16 cities24.7
- 10Bulgaria8 cities19.6
- 11Hungary11 cities18.5
- 12Chile46 cities18.2
- 13Peru18 cities18.0
- 14Romania10 cities18.0
- 15Taiwan43 cities18.0
- 16Mexico10 cities16.8
- 17Greece9 cities16.6
- 18Slovakia42 cities14.8
- 19South Korea141 cities13.9
- 20Spain113 cities13.0
+ 24 more countries, 12.9 µg/m³ and below
- 35United States819 cities6.7
Not counted on this day, too few cities measured: France since 18 Dec 2024, Martinique since 18 Dec 2024, Puerto Rico since 7 Dec 2024 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.