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 16 Dec 2023: Pakistan 130.2 µg/m³, India 96.2 µg/m³ and China 36.0 µg/m³.
- 1Pakistan4 cities130.2
- 2India4 cities96.2
- 3China3 cities36.0
- 4North Macedonia7 cities34.1
- 5Thailand9 cities31.9
- 6Serbia3 cities24.9
- 7Hong Kong13 cities20.9
- 8Slovakia27 cities18.1
- 9Chile39 cities17.8
- 10Mexico43 cities, was 1117.8
- 11Bulgaria5 cities17.6
- 12Czechia34 cities17.6
- 13Romania8 cities16.2
- 14Greece8 cities15.5
- 15Hungary7 cities15.5
- 16Lithuania3 cities14.5
- 17Italy23 cities14.4
- 18Austria29 cities13.0
- 19Belgium41 cities10.3
- 20France129 cities9.3
+ 15 more countries, 9.2 µg/m³ and below
- 26United States757 cities7.5
Not counted on this day, too few cities measured: Martinique since 8 Dec 2023, Ireland since 6 Nov 2023 and Peru since 21 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.