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 23 Nov 2023: Pakistan 117.7 µg/m³, India 94.7 µg/m³ and China 42.0 µg/m³.
- 1Pakistan4 cities117.7
- 2India4 cities94.7
- 3China3 cities42.0
- 4Thailand10 cities24.6
- 5North Macedonia7 cities19.4
- 6Chile31 cities18.9
- 7Hong Kong13 cities16.2
- 8Mexico37 cities, was 3714.6
- 9Serbia3 cities14.5
- 10Greece9 cities13.3
- 11Singapore5 cities12.0
- 12Romania7 cities11.7
- 13Bulgaria6 cities10.8
- 14Martinique3 cities10.5
- 15Hungary7 cities9.9
- 16Italy18 cities9.6
- 17Japan517 cities9.6
- 18Lithuania4 cities9.1
- 19Czechia31 cities8.6
- 20Slovakia27 cities8.5
+ 14 more countries, 7.7 µg/m³ and below
- 21United States773 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.