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 Jan 2024: Pakistan 215.1 µg/m³, India 72.5 µg/m³ and Serbia 44.5 µg/m³.
- 1Pakistan4 cities215.1
- 2India5 cities72.5
- 3Serbia12 cities, was 344.5
- 4North Macedonia7 cities39.4
- 5Montenegro3 cities35.3
- 6Thailand78 cities, was 1035.0
- 7Peru5 cities26.8
- 8Romania8 cities23.2
- 9China3 cities22.9
- 10Bulgaria6 cities21.6
- 11Hong Kong13 cities21.0
- 12Slovakia27 cities20.7
- 13Chile45 cities20.2
- 14Hungary9 cities19.0
- 15Italy24 cities18.2
- 16Czechia36 cities16.4
- 17Greece10 cities14.9
- 18South Africa27 cities14.2
- 19Mexico9 cities, was 4613.7
- 20Poland76 cities13.5
+ 21 more countries, the next at 13.4 µg/m³
- 36United States768 cities6.7
Not counted on this day, too few cities measured: Iceland since 26 Jan 2024, Reunion since 15 Jan 2024, Malta since 2 Jan 2024 and Martinique since 1 Dec 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, Turkey and Iran, which publish only on their own websites. We are building the reader for China's network. The networks of Turkey and Iran don't answer requests from outside their countries, so we can't read them. Most cities there are missing from this board, not clean. Why.