Found in bodies of water, the toxic blue-green algae grow more quickly as a result of rising atmospheric CO2 levels, and higher water temperatures.

The appearance of blooms large enough to prompt a ban on bathing at the end of the summer-start of autumn is becoming commonplace in Luxembourg.

A bloom was detected by the Romwiss beach in the Upper Sûre Lake on 24 August. At the time of publishing, bathing was still permitted at the rest of the lake and at the lake in Weiswampach. Updates on the situation can be found here.