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 Aug 2023: Pakistan 45.3 µg/m³, India 28.1 µg/m³ and China 27.5 µg/m³.
- 1Pakistan4 cities45.3
- 2India5 cities28.1
- 3China3 cities27.5
- 4Chile44 cities24.2
- 5Martinique3 cities19.9
- 6Malta4 cities16.3
- 7Serbia3 cities16.1
- 8Thailand11 cities15.8
- 9Slovakia27 cities15.7
- 10Czechia35 cities15.1
- 11Italy22 cities, was 2614.1
- 12Hungary7 cities13.6
- 13Canada117 cities13.5
- 14Greece7 cities13.3
- 15Romania7 cities12.9
- 16North Macedonia7 cities12.7
- 17Mexico11 cities12.1
- 18Singapore5 cities11.6
- 19Austria30 cities10.9
- 20Bulgaria6 cities10.9
+ 12 more countries, 10.8 µg/m³ and below
- 23United States754 cities9.8
Not counted on this day, too few cities measured: Australia since 21 Aug 2023, Hong Kong since 21 Aug 2023, Peru since 20 Aug 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.