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 22 Jul 2024: Chile 55.5 µg/m³, Peru 23.9 µg/m³ and China 20.0 µg/m³.
- 1Chile42 cities55.5
- 2Peru14 cities23.9
- 3China3 cities20.0
- 4North Macedonia9 cities19.4
- 5Singapore5 cities16.8
- 6Serbia22 cities15.4
- 7New Zealand5 cities14.8
- 8Malta4 cities14.4
- 9Slovakia41 cities14.1
- 10Italy10 cities14.0
- 11Romania10 cities12.6
- 12Bulgaria8 cities12.4
- 13Hungary11 cities11.6
- 14Czechia37 cities11.5
- 15Martinique3 cities11.3
- 16Greece6 cities11.2
- 17Thailand68 cities, was 7911.1
- 18Kosovo8 cities10.6
- 19Japan558 cities10.5
- 20India3 cities10.2
+ 25 more countries, 9.8 µg/m³ and below
- 25United States743 cities7.8
Not counted on this day, too few cities measured: Pakistan since 22 Jul 2024, Spain since 18 Jul 2024, Bosnia and Herzegovina since 14 Jul 2024 and 2 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.