“Despite some progress, full compliance has not yet been achieved”, highlights the Commission in a statement, which could take the case to the EU Court of Justice if non-compliance continues.

The reasoned opinion– the second step of the infringement process – “concerns 18 agglomerations in Portugal”, which Brussels does not identify.

According to the statement, “In 15 of these agglomerations, Portugal does not guarantee secondary or equivalent treatment of urban wastewater released into collection systems before discharge”.

In the remaining three, wastewater is discharged into sensitive areas without being subjected to more rigorous tertiary treatment.

Uncollected or untreated wastewater can endanger human health and pollute lakes, rivers, soil, coastal waters and groundwater.