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 18 Feb 2024: Pakistan 113.4 µg/m³, India 105.4 µg/m³ and Thailand 47.2 µg/m³.
- 1Pakistan4 cities113.4
- 2India5 cities105.4
- 3Thailand69 cities47.2
- 4Serbia22 cities35.9
- 5North Macedonia9 cities33.9
- 6Italy30 cities31.0
- 7Montenegro3 cities24.3
- 8Peru6 cities19.5
- 9Chile44 cities19.3
- 10Poland78 cities17.4
- 11Hong Kong13 cities16.7
- 12Romania10 cities16.7
- 13Bulgaria6 cities16.5
- 14Slovakia42 cities16.4
- 15Czechia38 cities14.5
- 16Hungary10 cities14.5
- 17Greece9 cities14.2
- 18Singapore5 cities12.9
- 19Mexico13 cities11.5
- 20Lithuania4 cities11.4
+ 19 more countries, 10.8 µg/m³ and below
- 34United States784 cities5.7
Not counted on this day, too few cities measured: China since 18 Feb 2024, Germany since 18 Feb 2024, Croatia since 18 Feb 2024 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.