Swimming has been banned in the Rhône and Arve rivers after a major sewerage discharge from a treatment plant in Annemasse.
The advice also extends to pets – dogs should not swim in the waters either.
A statement from canton Geneva says bacterial contamination is very high. Measurements were taken at the Etrembières bridge in France.
A similar problem also led to a ban of water activities in July.
The canton says there’s no risk to drinking water.
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