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 16 Sep 2023: Pakistan 45.7 µg/m³, Peru 28.8 µg/m³ and Chile 23.0 µg/m³.
- 1Pakistan4 cities45.7
- 2Peru4 cities28.8
- 3Chile43 cities23.0
- 4China3 cities20.3
- 5India5 cities18.6
- 6Malta4 cities15.7
- 7Singapore5 cities15.7
- 8Mexico40 cities15.5
- 9Poland60 cities15.2
- 10Czechia36 cities15.0
- 11Serbia3 cities13.6
- 12Italy30 cities13.1
- 13Slovakia27 cities12.7
- 14Hungary9 cities12.6
- 15Greece7 cities11.7
- 16Austria30 cities11.2
- 17Germany61 cities11.1
- 18Thailand10 cities11.1
- 19Belgium41 cities10.8
- 20Martinique3 cities10.4
+ 16 more countries, 10.1 µg/m³ and below
- 30United States749 cities6.6
Not counted on this day, too few cities measured: North Macedonia since 16 Sep 2023, Lithuania since 11 Sep 2023 and Luxembourg since 6 Sep 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 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.