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 6 Dec 2023: Pakistan 107.5 µg/m³, India 101.5 µg/m³ and China 34.2 µg/m³.
- 1Pakistan3 cities107.5
- 2India4 cities101.5
- 3China3 cities34.2
- 4North Macedonia7 cities27.6
- 5Thailand9 cities25.8
- 6Hong Kong13 cities20.5
- 7Serbia3 cities19.0
- 8Chile39 cities18.1
- 9Mexico40 cities, was 1117.1
- 10Bulgaria6 cities14.5
- 11Czechia30 cities14.1
- 12Romania7 cities13.9
- 13Slovakia27 cities13.6
- 14Hungary7 cities12.9
- 15Italy21 cities12.5
- 16Greece8 cities12.3
- 17Lithuania4 cities11.6
- 18Austria29 cities10.6
- 19Martinique3 cities10.0
- 20Singapore5 cities9.6
+ 15 more countries, 9.3 µg/m³ and below
- 25United States762 cities7.6
Not counted on this day, too few cities measured: 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.