According to the authority, "a strong alluvium caused by intense rain" was reflected "in microbiological values above the reference parameters".

The beaches of Santa Eulália, Alemães and Inatel, have all been declared as “unsuitable for swimming”.

"After receiving information from the Portuguese Environment Agency (APA) advising against going swimming on the beaches of Santa Eulália, Alemães and Inatel, the Algarve Health Delegate gave instructions for the red flag to be raised, warnings have been placed at the access points to the beaches, prohibiting swimming", says the AMN, in a statement.

The ban will remain in place until the results of water quality analyses indicate that microbiological values are within reference parameters.