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 30 days to 29 Aug 2023: Pakistan 38.3 µg/m³, Chile 34.5 µg/m³ and India 27.9 µg/m³.
- 1Pakistan4 cities38.3
- 2Chile44 cities34.5
- 3India5 cities27.9
- 4Peru3 cities26.3
- 5China3 cities22.8
- 6Brazil32 cities15.7
- 7Malta4 cities15.5
- 8Thailand11 cities14.7
- 9Mexico36 cities, was 1114.2
- 10Greece7 cities12.9
- 11Serbia3 cities12.4
- 12Singapore6 cities12.2
- 13Slovakia27 cities10.9
- 14Canada113 cities10.7
- 15Czechia28 cities10.7
- 16North Macedonia7 cities10.5
- 17Romania6 cities10.5
- 18Hungary7 cities10.2
- 19Italy11 cities10.2
- 20Bulgaria6 cities10.1
+ 16 more countries, the next at 10.1 µg/m³
- 22United States760 cities9.4
Not counted on this day, too few cities measured: Poland since 21 Aug 2023, Reunion since 16 Aug 2023, Lithuania since 27 Jul 2023 and Luxembourg since 27 Jul 2023.
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.