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 21 Jul 2023: Chile 46.3 µg/m³, Pakistan 37.7 µg/m³ and Peru 29.1 µg/m³.
- 1Chile46 cities46.3
- 2Pakistan4 cities37.7
- 3Peru3 cities29.1
- 4China3 cities28.3
- 5Malta3 cities26.8
- 6Martinique3 cities20.7
- 7Mexico38 cities, was 1214.9
- 8Greece8 cities13.9
- 9North Macedonia7 cities12.8
- 10Slovakia27 cities12.4
- 11Thailand11 cities12.4
- 12United States729 cities12.4
- 13Serbia3 cities12.3
- 14Singapore5 cities11.4
- 15Romania6 cities10.9
- 16Canada114 cities10.8
- 17Hungary8 cities10.8
- 18India5 cities10.6
- 19Spain78 cities9.7
- 20Bulgaria5 cities9.6
+ 11 more countries, 9.1 µg/m³ and below
Not counted on this day, too few cities measured: Switzerland since 16 Jul 2023, Italy since 16 Jul 2023, Lithuania since 16 Jul 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.