SmogRank / History / City race
Cities in Czechia, worst air first, day by day
Each measured city's average over the 30 days to every day since January 2023, worst first. Find your own city to follow it through the race, or keep to one country.
The worst cities in Czechia for PM2.5 over the 30 days to 25 Jan 2023: Děčín 18.8 µg/m³, Bohumín 18.0 µg/m³ and Havířov 17.7 µg/m³.
- 1DěčínÚstí nad Labem Region18.8
- 2BohumínMoravian-Silesian Region18.0
- 3HavířovMoravian-Silesian Region17.7
- 4Frýdek-MístekMoravian-Silesian Region17.5
- 5Český TěšínMoravian-Silesian Region16.9
- 6BerounCentral Bohemia16.0
- 7OstravaMoravian-Silesian Region15.9
- 8Valašské MeziříčíZlín15.4
- 9ZnojmoSouth Moravian14.7
- 10Hradec KrálovéHradec Králové Region14.0
- 11ZlínZlín13.9
- 12ŽideniceSouth Moravian13.2
- 13Ústí nad LabemÚstí nad Labem Region13.2
- 14OlomoucOlomouc Region13.2
- 15BrnoSouth Moravian12.9
- 16LitvínovÚstí nad Labem Region12.6
- 17MostÚstí nad Labem Region11.2
- 18LiberecLiberec Region11.0
- 19PraguePrague10.9
- 20PilsenPlzeň Region10.7
+ 1 more city, at 9.8 µg/m³
Days missing from the source archive fall in this window, so fewer countries are counted.
Cities counted each day
A city's number is its average over the 30 days, shown only when 21 of them were measured (5 of 7 on the 7-day race), the same minimum as the 30- and 7-day boards. A city whose monitors go quiet fades out where it stood rather than sliding down, so a gap never reads as cleaner air. 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.