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 17 May 2024: Chile 53.8 µg/m³, Pakistan 38.9 µg/m³ and China 30.3 µg/m³.
- 1Chile45 cities53.8
- 2Pakistan4 cities38.9
- 3China3 cities30.3
- 4India5 cities26.2
- 5Laos3 cities24.2
- 6Mexico11 cities23.9
- 7Peru12 cities22.8
- 8Thailand78 cities, was 1320.6
- 9New Zealand5 cities17.7
- 10Malta5 cities17.0
- 11Taiwan43 cities15.6
- 12Hong Kong13 cities14.2
- 13South Korea141 cities12.6
- 14Puerto Rico3 cities11.8
- 15Singapore5 cities11.5
- 16United Kingdom63 cities, was 1111.0
- 17Ireland6 cities11.0
- 18The Netherlands36 cities10.6
- 19Serbia24 cities10.5
- 20Latvia4 cities9.9
+ 29 more countries, 9.7 µg/m³ and below
- 41United States791 cities6.1
Not counted on this day, too few cities measured: Austria since 10 May 2024, Bosnia and Herzegovina since 26 Apr 2024 and Montenegro since 22 Mar 2024.
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.