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 3 Apr 2023: Laos 59.1 µg/m³, India 46.2 µg/m³ and China 45.6 µg/m³.
- 1Laos3 cities59.1
- 2India3 cities46.2
- 3China4 cities45.6
- 4Pakistan4 cities31.6
- 5Mexico46 cities27.1
- 6Thailand78 cities26.9
- 7Chile45 cities24.8
- 8Peru5 cities15.7
- 9South Africa12 cities14.6
- 10Hong Kong12 cities14.0
- 11Greece8 cities12.6
- 12Brazil13 cities11.9
- 13Romania7 cities11.0
- 14Poland66 cities10.8
- 15Czechia25 cities9.7
- 16Slovakia24 cities9.5
- 17Italy20 cities9.1
- 18Bulgaria7 cities8.9
- 19Singapore5 cities8.5
- 20Spain90 cities8.1
+ 17 more countries, 7.5 µg/m³ and below
- 25United States682 cities6.5
Not counted on this day, too few cities measured: Sweden since 29 Mar 2023, Kosovo since 28 Mar 2023, Bosnia and Herzegovina since 22 Mar 2023 and 5 more countries.
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.