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 16 Sep 2023: Pakistan 41.8 µg/m³, Chile 27.1 µg/m³ and Peru 26.5 µg/m³.
- 1Pakistan4 cities41.8
- 2Chile43 cities27.1
- 3Peru4 cities26.5
- 4India5 cities24.0
- 5China3 cities22.3
- 6Mexico35 cities15.3
- 7Singapore5 cities14.7
- 8Malta4 cities14.0
- 9Thailand11 cities13.7
- 10Greece7 cities13.3
- 11Serbia3 cities13.3
- 12Czechia35 cities12.3
- 13Hungary8 cities12.0
- 14Slovakia27 cities12.0
- 15North Macedonia7 cities11.7
- 16Italy27 cities11.2
- 17United Kingdom4 cities, was 3211.0
- 18Martinique3 cities10.6
- 19Belgium41 cities10.2
- 20Bulgaria6 cities10.1
+ 15 more countries, 9.8 µg/m³ and below
- 25United States763 cities9.0
Not counted on this day, too few cities measured: Poland since 21 Aug 2023, Reunion since 16 Aug 2023, Lithuania since 27 Jul 2023 and Luxembourg since 27 Jul 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.