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 Aug 2024: Chile 36.1 µg/m³, Pakistan 34.6 µg/m³ and Peru 26.7 µg/m³.
- 1Chile45 cities36.1
- 2Pakistan4 cities34.6
- 3Peru13 cities26.7
- 4China3 cities24.4
- 5India5 cities17.3
- 6Serbia11 cities16.2
- 7Hungary5 cities15.3
- 8Singapore5 cities14.9
- 9South Korea141 cities14.4
- 10Poland71 cities13.5
- 11Hong Kong12 cities13.4
- 12Thailand15 cities, was 913.2
- 13Taiwan43 cities12.5
- 14Mexico4 cities8.8
- 15The Netherlands20 cities8.8
- 16United States805 cities8.3
- 17Bulgaria5 cities8.1
- 18United Kingdom60 cities7.2
- 19Canada117 cities6.7
- 20Norway16 cities6.5
+ 3 more countries, 6.1 µg/m³ and below
Not counted on this day, too few cities measured: Iceland since 30 Aug 2024, Belgium since 17 Aug 2024, Switzerland since 17 Aug 2024 and 23 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.