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 24 Jul 2023: Chile 41.7 µg/m³, Pakistan 32.7 µg/m³ and China 30.1 µg/m³.
- 1Chile46 cities41.7
- 2Pakistan4 cities32.7
- 3China3 cities30.1
- 4Malta4 cities28.8
- 5Peru4 cities25.3
- 6Martinique3 cities20.5
- 7Greece8 cities17.0
- 8Italy30 cities, was 2614.4
- 9Mexico39 cities, was 1214.0
- 10North Macedonia7 cities13.7
- 11Thailand11 cities12.5
- 12Singapore5 cities12.0
- 13Bulgaria5 cities11.8
- 14Serbia3 cities11.4
- 15Slovakia27 cities11.4
- 16United States737 cities10.9
- 17Romania6 cities9.6
- 18India5 cities9.4
- 19Canada115 cities9.3
- 20Hungary8 cities8.9
+ 16 more countries, 8.8 µg/m³ and below
Not counted on this day, too few cities measured: Lithuania since 16 Jul 2023, Luxembourg since 16 Jul 2023, The Netherlands since 24 Jun 2023 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.