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 26 Nov 2023: Pakistan 114.4 µg/m³, India 110.8 µg/m³ and China 46.8 µg/m³.
- 1Pakistan3 cities114.4
- 2India4 cities110.8
- 3China3 cities46.8
- 4North Macedonia7 cities33.7
- 5Thailand11 cities31.2
- 6Serbia3 cities28.0
- 7Hong Kong13 cities21.8
- 8Chile38 cities, was 4318.3
- 9Romania7 cities17.8
- 10Mexico45 cities16.3
- 11Bulgaria6 cities14.5
- 12Hungary8 cities13.0
- 13Greece8 cities12.7
- 14Italy23 cities12.1
- 15Martinique3 cities10.3
- 16Slovakia25 cities10.1
- 17Czechia26 cities9.9
- 18Japan510 cities9.0
- 19Spain107 cities8.9
- 20Belgium41 cities8.7
+ 16 more countries, 8.5 µg/m³ and below
- 25United States752 cities6.8
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.