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 31 Jul 2024: Chile 50.8 µg/m³, Pakistan 38.2 µg/m³ and China 19.9 µg/m³.
- 1Chile41 cities50.8
- 2Pakistan4 cities38.2
- 3China4 cities19.9
- 4Peru16 cities19.2
- 5India4 cities17.4
- 6Singapore5 cities17.4
- 7New Zealand5 cities15.5
- 8Malta5 cities14.1
- 9Italy11 cities13.5
- 10Martinique3 cities12.1
- 11Thailand15 cities, was 7911.9
- 12North Macedonia9 cities11.2
- 13Greece6 cities10.8
- 14Mexico3 cities10.3
- 15Slovakia40 cities9.2
- 16United States798 cities9.2
- 17Canada120 cities8.6
- 18Switzerland9 cities8.6
- 19Belgium43 cities8.3
- 20Slovenia12 cities8.1
+ 26 more countries, 8.0 µg/m³ and below
Not counted on this day, too few cities measured: Austria since 30 Jul 2024, Spain since 18 Jul 2024 and Bosnia and Herzegovina since 14 Jul 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.