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 21 Oct 2023: India 70.3 µg/m³, Pakistan 45.0 µg/m³ and Thailand 28.1 µg/m³.
- 1India4 cities70.3
- 2Pakistan4 cities45.0
- 3Thailand10 cities28.1
- 4Chile46 cities21.0
- 5China3 cities19.5
- 6Serbia3 cities18.2
- 7Singapore5 cities17.8
- 8Malta4 cities17.6
- 9Czechia35 cities15.1
- 10Romania7 cities13.4
- 11North Macedonia7 cities13.0
- 12Hungary6 cities12.6
- 13Mexico11 cities, was 4212.1
- 14Greece9 cities11.9
- 15Austria30 cities10.7
- 16Slovakia26 cities10.7
- 17Bulgaria6 cities8.9
- 18Japan527 cities8.7
- 19Italy27 cities8.5
- 20Germany59 cities7.8
+ 13 more countries, 6.6 µg/m³ and below
- 26United States759 cities5.6
Not counted on this day, too few cities measured: Martinique since 18 Oct 2023, Hong Kong since 17 Oct 2023, Peru since 17 Oct 2023 and 3 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.