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 Oct 2023: India 77.0 µg/m³, Pakistan 44.5 µg/m³ and Peru 31.8 µg/m³.
- 1India4 cities77.0
- 2Pakistan4 cities44.5
- 3Peru5 cities31.8
- 4China3 cities31.4
- 5Singapore5 cities24.0
- 6Thailand10 cities21.8
- 7Chile45 cities21.6
- 8Serbia3 cities17.5
- 9North Macedonia7 cities16.5
- 10Malta4 cities16.5
- 11Hong Kong11 cities, was 1315.1
- 12Hungary9 cities14.0
- 13Mexico38 cities13.6
- 14Italy31 cities13.4
- 15Greece9 cities12.6
- 16Romania7 cities12.3
- 17Slovakia27 cities12.3
- 18Portugal10 cities11.5
- 19Czechia35 cities10.9
- 20Spain57 cities10.0
+ 15 more countries, 9.8 µg/m³ and below
- 32United States763 cities5.3
Not counted on this day, too few cities measured: Reunion since 11 Oct 2023, Poland since 1 Oct 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.