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 May 2023: Pakistan 36.2 µg/m³, India 35.1 µg/m³ and China 34.9 µg/m³.
- 1Pakistan4 cities36.2
- 2India3 cities35.1
- 3China4 cities34.9
- 4Chile42 cities29.4
- 5Thailand76 cities27.5
- 6Mexico42 cities24.6
- 7South Africa10 cities18.0
- 8Serbia18 cities16.4
- 9Hong Kong12 cities15.3
- 10Czechia30 cities14.1
- 11Greece8 cities13.7
- 12Belgium37 cities13.2
- 13Slovakia24 cities12.1
- 14Poland63 cities11.8
- 15United Kingdom5 cities10.9
- 16Austria23 cities10.5
- 17Hungary7 cities10.4
- 18Romania7 cities9.1
- 19Germany183 cities8.8
- 20Italy23 cities8.8
+ 16 more countries, 8.5 µg/m³ and below
- 30United States690 cities5.8
Not counted on this day, too few cities measured: Luxembourg since 25 Apr 2023, Peru since 22 Apr 2023, Laos since 9 Apr 2023 and 8 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.