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 May 2023: Chile 42.2 µg/m³, Pakistan 33.7 µg/m³ and China 30.5 µg/m³.
- 1Chile46 cities42.2
- 2Pakistan4 cities33.7
- 3China3 cities30.5
- 4India5 cities28.9
- 5Thailand10 cities, was 7722.8
- 6Mexico13 cities, was 4719.2
- 7Serbia3 cities, was 2114.8
- 8Slovakia26 cities13.3
- 9Malta3 cities13.2
- 10Italy27 cities12.0
- 11Hungary8 cities10.8
- 12Czechia35 cities10.6
- 13Greece7 cities10.4
- 14France129 cities10.2
- 15Switzerland9 cities9.9
- 16Belgium38 cities9.8
- 17Romania6 cities9.7
- 18Lithuania3 cities9.5
- 19Singapore5 cities9.4
- 20Spain97 cities8.9
+ 12 more countries, 8.7 µg/m³ and below
- 25United States724 cities7.4
Not counted on this day, too few cities measured: Poland since 29 May 2023, Luxembourg since 28 May 2023, Australia since 27 May 2023 and 8 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.