In its ruling, the EU's Court of Justice has found Portugal guilty of failing to implement a directive relating to waste water in two urban areas at opposite ends of the country: Vila Real de Santo António, in the Algarve, and Matosinhos, near Porto.

In 2009, Portugal had been found guilty by the court of failing to implement the same directive in 22 urban areas. In 2015 the European Commission took up the matter again, this time with regard only to Vila Real de Santo António and Matosinhos.

For its part, Portugal argued that the 2009 ruling has mostly been executed.

In Vila Real de Santo António work to improve the waste-water network was concluded on 11 April 2015. In the case of Matosinhos, Portugal argued that the existing primary treatment is sufficient to guarantee the quality of water and avoid risks to the environment and human health and that steps have been taken to execute the 2009 ruling, even though the the planned treatment plant has not been built because of financing difficulties.

The court has now ruled that "Portugal has not met its obligation of executing the 2009 ruling, in that within the deadline set by the Commission for the execution of this ruling (21 April 2014), the two localities in question still did not have urban waste-water treatment systems."

In setting the fine at €3 million, the court took into account other failings on the part of Portugal in this field and the fact that health and the environment are under threat. It deemed that the size of fine chosen is of a dissuasive nature.

As for the additional daily fine, the court took the view that the particularly lengthy nature of the infringement was another aggravating circumstance.

According to the Portuguese authorities, the 2009 ruling is only likely to be fully executed in 2019 - equivalent to a delay of almost 20 years relative to the obligation to assure the level of secondary waste-water treatment, which was to have been fulfilled by 31 December 2000.

Taking into account the fact that it is only in Matosinhos that such treatment is not assured, and Portugal's limited financial capacity, the court took the view that a daily fine of €8,000 was suitable.