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 23 Jul 2023: Chile 42.1 µg/m³, Pakistan 34.2 µg/m³ and China 28.9 µg/m³.
- 1Chile46 cities42.1
- 2Pakistan4 cities34.2
- 3China3 cities28.9
- 4Malta4 cities27.5
- 5Peru3 cities27.2
- 6Martinique3 cities20.5
- 7Greece8 cities16.0
- 8Mexico40 cities, was 1214.5
- 9North Macedonia7 cities14.3
- 10Italy5 cities, was 2614.0
- 11Singapore5 cities12.2
- 12Thailand11 cities12.2
- 13Serbia3 cities11.8
- 14Slovakia27 cities11.7
- 15United States734 cities11.6
- 16Canada115 cities11.0
- 17Bulgaria5 cities10.0
- 18Romania6 cities10.0
- 19Hungary8 cities9.7
- 20India5 cities9.4
+ 16 more countries, 9.3 µg/m³ and below
Not counted on this day, too few cities measured: Lithuania since 16 Jul 2023, Luxembourg since 16 Jul 2023, The Netherlands since 24 Jun 2023 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.