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 2 Apr 2024: Laos 61.6 µg/m³, India 44.3 µg/m³ and Pakistan 43.2 µg/m³.
- 1Laos3 cities61.6
- 2India5 cities44.3
- 3Pakistan4 cities43.2
- 4Malta4 cities40.1
- 5China4 cities38.4
- 6Thailand84 cities, was 7825.8
- 7Chile43 cities22.8
- 8Hong Kong8 cities21.9
- 9Bosnia and Herzegovina5 cities21.5
- 10South Korea123 cities20.9
- 11Greece7 cities20.7
- 12Taiwan43 cities19.0
- 13Czechia37 cities18.9
- 14Mexico20 cities18.6
- 15Poland77 cities17.6
- 16Latvia4 cities17.5
- 17Slovenia12 cities17.1
- 18Lithuania4 cities16.9
- 19Hungary10 cities, was 1016.6
- 20North Macedonia8 cities16.4
+ 27 more countries, 15.4 µg/m³ and below
- 36United States784 cities6.2
Not counted on this day, too few cities measured: Montenegro since 22 Mar 2024, Austria since 13 Mar 2024, Switzerland since 13 Mar 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.