A criminal gang that trafficked tonnes of stolen waste cardboard from Madrid to Asian countries has been shut down, Spanish police say.
More than 40 suspected gang members have been arrested on suspicion of environmental offences and money laundering.
The gang has been accused of illegally shipping over 67,000 tonnes of waste worth €10 million (£8.4m).
Much of the waste was stolen from council-owned recycling bins.
A waste management company based in Madrid has been organising the illegal collection of paper and cardboard since 2015, police said.
The criminal gang is estimated to have cost Madrid city council around €16 million through loss of recyclable materials.
Paper and cardboard deposited in banks is sold on to recycling plants and converted back into raw materials.
The paper and cardboard that was stolen by the gang was mixed with legally collected waste before being shipped to countries in South East Asia, mainly China, India, Indonesia and South Korea.
Pictures released by police show a suspect with his legs dangling out of a council recycling bin as he attempts to steal the cardboard and paper inside.
A police source told the El Pais newspaper that members of the gang sometimes “went twice in a day for the paper” in “the most juicy areas”.
Of the 42 people arrested, three were Spanish nationals and most others were of Romanian origin.
Eleven trucks used in the theft of waste were also seized as part of the police crackdown, named Operation Hartie.
The operation, which was led by the Spanish Civil Guard (Guardia Civil), was supported by Europol, the law enforcement agency of the European Union (EU).
Organised crime has been linked with the waste disposal industry in several European countries, most notably Italy.
A 2015 report by the EU said organised crime in Italy “plays a significant role in the waste management industry, particularly in the area of illegal dumping and international illegal trafficking of hazardous waste”.