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 21 Jul 2024: Chile 52.3 µg/m³, Pakistan 29.2 µg/m³ and China 22.4 µg/m³.
- 1Chile44 cities52.3
- 2Pakistan3 cities29.2
- 3China3 cities22.4
- 4Peru15 cities20.5
- 5New Zealand5 cities17.4
- 6India4 cities16.6
- 7Serbia24 cities13.8
- 8Malta5 cities13.7
- 9North Macedonia8 cities13.2
- 10Slovakia41 cities13.0
- 11Italy10 cities11.9
- 12Singapore5 cities11.8
- 13Thailand18 cities, was 8011.6
- 14Hungary10 cities11.4
- 15Greece6 cities11.1
- 16South Korea141 cities10.9
- 17Slovenia12 cities10.8
- 18Romania9 cities9.9
- 19Japan559 cities9.3
- 20Poland72 cities9.2
+ 25 more countries, 9.0 µg/m³ and below
- 24United States795 cities7.5
Not counted on this day, too few cities measured: Bosnia and Herzegovina since 20 Jul 2024, Czechia since 11 Jun 2024, Laos since 8 Jun 2024 and Croatia since 6 Jun 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.