DALIAN, Dec. 19 (Xinhua) -- Customs officers in the coastal city of Dalian in northeast China's Liaoning Province intercepted over 600 tonnes of smuggled solid waste and arrested three suspects on Wednesday.

The Dalian Customs said the suspects had falsely declared the solid waste and used an import license of a local company for smuggling. Further investigation is underway.

The Dalian Customs has launched three rounds of a crackdown on trash smuggling this year and intercepted over 5,600 tonnes of illegal solid waste imports.

China began importing solid waste as a source of raw materials in the 1980s and for years has been the world's largest importer.

Given rising public awareness of environmental protection and China's green development drive, the country decided to phase out and halt such imports by the end of 2019.