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 22 May 2023: Pakistan 39.3 µg/m³, Chile 33.9 µg/m³ and South Africa 31.9 µg/m³.
- 1Pakistan4 cities39.3
- 2Chile45 cities33.9
- 3South Africa6 cities31.9
- 4India5 cities29.7
- 5Thailand64 cities, was 7729.2
- 6Mexico12 cities, was 4720.7
- 7Serbia3 cities, was 2114.3
- 8Hong Kong12 cities13.4
- 9Greece7 cities12.9
- 10Czechia35 cities12.8
- 11Singapore5 cities12.2
- 12Belgium41 cities11.1
- 13Bulgaria6 cities11.0
- 14Luxembourg3 cities11.0
- 15Poland63 cities9.8
- 16Austria30 cities9.7
- 17Ireland4 cities9.7
- 18Slovakia26 cities9.7
- 19Germany193 cities9.6
- 20Romania6 cities9.5
+ 18 more countries, 9.5 µg/m³ and below
- 21United States742 cities9.5
Not counted on this day, too few cities measured: Martinique since 20 May 2023, China since 10 May 2023, Laos since 10 May 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.