In a statement outlining details of the complaint, ClientEarth and Spain’s Ecologists in Action urge the European Commission to take “immediate action against Spain” as harmful agricultural practices were pushing the lagoon “to the brink of ecological collapse”.

It said the “continuous build-up of fertilisers from nearby agricultural land has created toxic conditions in the Mar Menor” which breach both EU and Spanish laws.

In August, millions of dead fish and crustaceans began washing up on the shores of the Mar Menor, located on Spain’s southeastern coast, which experts have repeatedly blamed on agricultural pollution.

They argue that sealife died due to a lack of oxygen caused by hundreds of tonnes of fertiliser nitrates leaking into the waters causing a phenomenon known as eutrophication which collapses aquatic ecosystems.

Two similar catastrophic pollution events occurred in 2016 and 2019.

Although the lagoon is protected under various EU directives and the UN environment programme, Spain had failed to comply with its legal obligations, taking “only superficial steps to safeguard the Mar Menor from damaging agricultural practices”, the environmental groups said.

READ ALSO: Five stats to understand why Spain’s Mar Menor is full of dead fish

“The European Commission must urgently act to stop this environmental crisis. As legal guardian of the Mar Menor, the Spanish authorities have a duty to safeguard the lagoon.. which risks disappearing forever,” ClientEarth lawyer Soledad Gallego said in a statement.

“Spain’s lack of meaningful action to protect this iconic site means we are witnessing the Mar Menor breaking down before our eyes. Protected species and habitats clearly cannot survive, let alone thrive, under the suffocating conditions caused by current industrial farming.”

Spain’s environment minister has accused the regional authorities of turning a blind eye to farming irregularities in the Campo de Cartagena, a vast area of intensive agriculture surrounding the lagoon.

But agricultural groups insist they comply scrupulously with environmental legislation.

If intensive agricultural practices are not curbed, there will be damaging long-term consequences, the NGOs warned.

“Continuing to compromise the Mar Menor and the surrounding farmland in favour of short-term gains is already causing irreversible harm and will eventually leave the area barren, which will have environmental as well as economic and social repercussions,” said Gallego.

Experts at Ecologists in Action believe the lagoon could recover if the area of irrigated land was reduced, if stricter limits were imposed on the use of fertilisers and if natural solutions were found to help retain excess nutrients and prevent soil loss.

Activists, who held a mass demonstration in August, are planning a new rally on Thursday evening in the city of Murcia to demand urgent action to save the lagoon.