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 20 Nov 2023: Pakistan 124.7 µg/m³, India 97.7 µg/m³ and China 34.4 µg/m³.
- 1Pakistan4 cities124.7
- 2India4 cities97.7
- 3China3 cities34.4
- 4North Macedonia7 cities26.8
- 5Thailand9 cities21.7
- 6Chile39 cities, was 4319.2
- 7Mexico42 cities18.0
- 8Hong Kong13 cities17.7
- 9Serbia3 cities16.2
- 10Martinique3 cities15.2
- 11Italy22 cities12.9
- 12Romania7 cities11.9
- 13Greece7 cities10.8
- 14Lithuania4 cities10.5
- 15Bulgaria6 cities10.4
- 16Spain108 cities10.1
- 17Singapore5 cities9.1
- 18Hungary9 cities8.6
- 19Belgium41 cities8.4
- 20Slovakia27 cities7.8
+ 15 more countries, 7.8 µg/m³ and below
- 21United States761 cities7.8
Not counted on this day, too few cities measured: Ireland since 31 Oct 2023, Peru since 17 Oct 2023 and Poland since 1 Oct 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.