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 Sep 2023: Pakistan 70.6 µg/m³, India 29.4 µg/m³ and China 26.3 µg/m³.
- 1Pakistan4 cities70.6
- 2India4 cities29.4
- 3China3 cities26.3
- 4Chile44 cities21.7
- 5Singapore5 cities20.7
- 6Greece6 cities16.3
- 7Mexico39 cities16.1
- 8Thailand10 cities14.7
- 9Poland44 cities13.5
- 10Czechia36 cities13.3
- 11Hungary10 cities12.3
- 12Serbia3 cities12.2
- 13Malta4 cities11.9
- 14Italy27 cities11.5
- 15Canada116 cities10.5
- 16Slovakia26 cities10.5
- 17North Macedonia7 cities10.3
- 18Hong Kong13 cities9.9
- 19Romania7 cities9.9
- 20Austria30 cities9.6
+ 15 more countries, 8.9 µg/m³ and below
- 28United States761 cities6.7
Not counted on this day, too few cities measured: Peru since 30 Sep 2023, Reunion since 26 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.