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 21 Nov 2023: Pakistan 110.4 µg/m³, India 91.1 µg/m³ and China 44.7 µg/m³.
- 1Pakistan4 cities110.4
- 2India4 cities91.1
- 3China3 cities44.7
- 4Thailand10 cities23.1
- 5Chile24 cities18.8
- 6North Macedonia7 cities18.7
- 7Hong Kong13 cities15.8
- 8Mexico35 cities, was 3715.0
- 9Serbia3 cities13.6
- 10Greece9 cities13.5
- 11Singapore5 cities12.4
- 12Romania6 cities11.3
- 13Martinique3 cities10.4
- 14Bulgaria6 cities10.0
- 15Italy18 cities9.8
- 16Hungary7 cities9.5
- 17Japan518 cities9.2
- 18Lithuania4 cities8.9
- 19Slovakia27 cities8.4
- 20Czechia31 cities8.1
+ 14 more countries, 7.7 µg/m³ and below
- 21United States774 cities7.7
Not counted on this day, too few cities measured: Malta since 11 Nov 2023, Ireland since 6 Nov 2023, Peru since 21 Oct 2023 and Poland since 8 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.