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 22 Jul 2023: Chile 43.0 µg/m³, Pakistan 37.0 µg/m³ and Malta 27.9 µg/m³.
- 1Chile46 cities43.0
- 2Pakistan4 cities37.0
- 3Malta4 cities27.9
- 4Peru3 cities27.8
- 5China3 cities27.7
- 6Martinique3 cities21.1
- 7Greece8 cities15.2
- 8Mexico40 cities, was 1214.4
- 9North Macedonia7 cities13.9
- 10United States739 cities12.1
- 11Serbia3 cities12.0
- 12Slovakia27 cities11.9
- 13Thailand11 cities11.8
- 14Singapore5 cities11.6
- 15Canada114 cities11.0
- 16Romania6 cities10.3
- 17Hungary8 cities10.2
- 18India5 cities10.2
- 19Bulgaria5 cities9.6
- 20Spain90 cities9.3
+ 14 more countries, 9.1 µg/m³ and below
Not counted on this day, too few cities measured: Italy since 16 Jul 2023, Lithuania since 16 Jul 2023, Luxembourg since 16 Jul 2023 and 5 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.