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 19 Nov 2023: India 110.9 µg/m³, Pakistan 105.9 µg/m³ and China 28.0 µg/m³.
- 1India4 cities110.9
- 2Pakistan3 cities105.9
- 3China3 cities28.0
- 4North Macedonia7 cities23.2
- 5Thailand9 cities19.8
- 6Chile39 cities, was 4319.1
- 7Mexico43 cities16.2
- 8Hong Kong13 cities16.0
- 9Serbia3 cities14.2
- 10Italy22 cities11.9
- 11Romania7 cities11.5
- 12Bulgaria6 cities10.8
- 13Singapore5 cities10.1
- 14Spain105 cities9.5
- 15Hungary9 cities9.2
- 16Lithuania4 cities9.1
- 17Czechia30 cities8.8
- 18Greece9 cities8.6
- 19Belgium41 cities8.4
- 20United States763 cities8.1
+ 14 more countries, 7.9 µg/m³ and below
Not counted on this day, too few cities measured: Martinique since 15 Nov 2023, Ireland since 31 Oct 2023, Peru since 17 Oct 2023 and Poland since 1 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.