Czech health authorities have issued the first swimming ban of the year at Kachlička Pond in the Havlíčkobrod region due to a dangerous bloom of cyanobacteria, commonly known as blue-green algae. The high concentration of these toxins poses an immediate health risk to swimmers. Water quality at Domanínský Pond near Žďár and Stříbrný Pond in Hradec Králové is also reported to be poor, though not yet subject to a complete ban. Officials warn that exposure to the algae can cause acute health problems. This marks the first official prohibition of swimming at a Czech water body this season. Further monitoring of recreational waters is ongoing to assess potential risks. The ban at Kachlička Pond will remain in effect until water quality improves.