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 20 Mar 2024: India 51.0 µg/m³, Pakistan 50.4 µg/m³ and China 41.6 µg/m³.
- 1India5 cities51.0
- 2Pakistan3 cities50.4
- 3China3 cities41.6
- 4Poland71 cities25.2
- 5Serbia16 cities23.7
- 6Thailand17 cities, was 7223.1
- 7Hong Kong13 cities19.1
- 8Montenegro3 cities19.1
- 9Chile43 cities18.5
- 10Bulgaria4 cities18.2
- 11Peru6 cities17.1
- 12Mexico12 cities14.7
- 13Hungary3 cities, was 913.9
- 14Singapore5 cities11.6
- 15The Netherlands21 cities8.8
- 16Norway18 cities8.5
- 17United Kingdom59 cities7.8
- 18Japan494 cities7.6
- 19United States780 cities6.2
- 20Canada109 cities5.6
+ 2 more countries, 5.5 µg/m³ and below
Not counted on this day, too few cities measured: Belgium since 20 Mar 2024, Switzerland since 20 Mar 2024, Czechia since 20 Mar 2024 and 18 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.