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 9 Jul 2023: Chile 43.3 µg/m³, Pakistan 38.0 µg/m³ and India 21.3 µg/m³.
- 1Chile46 cities43.3
- 2Pakistan4 cities38.0
- 3India5 cities21.3
- 4China3 cities21.0
- 5Mexico11 cities16.1
- 6Thailand11 cities12.7
- 7Malta4 cities12.6
- 8Greece8 cities12.1
- 9Czechia36 cities11.5
- 10Serbia3 cities11.4
- 11Slovakia27 cities11.4
- 12Canada105 cities11.0
- 13Belgium41 cities10.4
- 14Luxembourg3 cities10.4
- 15Italy28 cities10.1
- 16Martinique3 cities10.1
- 17United States752 cities10.1
- 18Lithuania4 cities10.0
- 19Hungary8 cities9.8
- 20Romania6 cities9.7
+ 13 more countries, 9.5 µg/m³ and below
Not counted on this day, too few cities measured: Poland since 29 May 2023, The Netherlands since 23 May 2023 and Norway since 19 May 2023.
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.