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 21 Nov 2023: Pakistan 131.2 µg/m³, India 92.2 µg/m³ and China 35.6 µg/m³.
- 1Pakistan4 cities131.2
- 2India4 cities92.2
- 3China3 cities35.6
- 4North Macedonia7 cities30.2
- 5Thailand9 cities24.1
- 6Serbia3 cities19.8
- 7Mexico45 cities19.4
- 8Chile38 cities, was 4318.6
- 9Hong Kong13 cities17.3
- 10Martinique3 cities17.0
- 11Italy22 cities13.6
- 12Romania7 cities12.7
- 13Greece7 cities11.6
- 14Bulgaria6 cities11.1
- 15Lithuania4 cities10.1
- 16Hungary8 cities10.0
- 17Spain108 cities9.3
- 18Belgium41 cities8.5
- 19Czechia28 cities8.4
- 20Slovakia27 cities8.4
+ 15 more countries, 8.0 µg/m³ and below
- 22United States764 cities7.6
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.