A total of 48 beaches in Spain have been issued with a "black flag" for issues including chemical spills, dog poo and invasive developments.
The beaches were named by Spanish environmental campaign group, Ecologists in Action, which slammed authorities for not looking after the coastal areas.
Many of the beaches, which formed part of a damning report, are popular with tourists from abroad.
One beach on the list, A Calzoa in Vigo, on the north west coast, has been described as the "worst dog beach in Spain", reports The Sun and according to local media has become a "sandbox for dogs", ruined with droppings.
Other beaches listed in the report include those in Malaga as well as some in the Canary Islands, Catalonia, Balearic Islands and Basque Country.
Twelve of the black flag classifications were due to chemical spills, faulty sanitation and purification problems, the group said.
Six, meanwhile, were due to chemical, light or noise pollution.
A number of the issues have been caused by over-development of land and poor management by authorities, according to the report.
Last month the Mirror shared Spain's top ten unspoilt beaches, following research by Avis.
The company scoured three million Google searches to pinpoint the most secluded Blue Flag beaches in the country, perfect for anyone wanted to escape the crowds.
Topping the list is Os Frades beach, a pristine spot nestled in the hills of the Baiona coastline. Oj Frades is a relatively small beach but is known for its crystal-clear waters and picturesque views.
It is accessed by a winding path that offers breath-taking views of the coastline by Monterreal Fortress, a towering castle built in the 12th century. A hidden gem in the Galician coast, the beach’s fine golden sand and scattered rock formations make it the ideal spot for a relaxing day out.
Ezaro Beach is another unspoiled spot located on the west coast of Spain. It is surrounded by impressive cliffs and is accessible only by foot, which adds to its peaceful atmosphere.
In addition to its natural beauty and surfing opportunities, Ezaro Beach is steeped in cultural and historical significance. The beach is located near the famous Camino de Santiago, a pilgrimage route that dates back to the Middle Ages and still sees thousands of pilgrims walk across the north of the country each year.
You can see the full list here.
For the full Black Flag list visit Ecologists in Action's website.
