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 Jun 2023: Chile 34.9 µg/m³, Pakistan 33.2 µg/m³ and China 23.3 µg/m³.
- 1Chile46 cities34.9
- 2Pakistan4 cities33.2
- 3China3 cities23.3
- 4Peru3 cities23.2
- 5Brazil33 cities16.7
- 6India5 cities15.2
- 7Malta4 cities13.9
- 8Mexico15 cities13.3
- 9Thailand10 cities12.9
- 10Greece8 cities11.6
- 11Singapore6 cities11.0
- 12United States741 cities10.4
- 13Spain87 cities10.1
- 14Italy24 cities9.7
- 15Czechia35 cities9.6
- 16Slovakia26 cities9.4
- 17Canada109 cities9.0
- 18Belgium41 cities8.9
- 19Switzerland9 cities8.6
- 20Germany207 cities8.5
+ 15 more countries, the next at 8.5 µg/m³
Not counted on this day, too few cities measured: Luxembourg since 24 Jun 2023, The Netherlands since 24 Jun 2023, Poland since 24 Jun 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, Turkey and Iran, which publish only on their own websites. We are building the reader for China's network. The networks of Turkey and Iran don't answer requests from outside their countries, so we can't read them. Most cities there are missing from this board, not clean. Why.