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 2 Jul 2023: Chile 39.3 µg/m³, Pakistan 29.3 µg/m³ and China 25.8 µg/m³.
- 1Chile46 cities39.3
- 2Pakistan4 cities29.3
- 3China3 cities25.8
- 4Peru3 cities25.0
- 5India5 cities15.8
- 6Mexico12 cities14.5
- 7Malta4 cities13.2
- 8Greece8 cities12.9
- 9Thailand11 cities12.2
- 10United States739 cities11.8
- 11Italy17 cities10.6
- 12Martinique3 cities10.6
- 13Slovakia26 cities10.6
- 14Luxembourg3 cities10.2
- 15Czechia36 cities9.7
- 16North Macedonia7 cities9.5
- 17Serbia3 cities9.5
- 18Hungary8 cities9.4
- 19Singapore5 cities9.4
- 20Belgium41 cities8.9
+ 14 more countries, 8.8 µg/m³ and below
Not counted on this day, too few cities measured: Spain since 1 Jul 2023, The Netherlands since 24 Jun 2023, Poland since 24 Jun 2023 and 6 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.