The waste, which came in 10 large containers, was declared as mixed metal scrap but turned out to be circuit boards mixed in a huge pile of metal scrap, said Theeraj Athanavanich, director-general of the Customs Department.

The waste was found on Tuesday after the containers became the subject of a routine random inspection, officials said.

A U.N. report last year said electronic waste is piling up worldwide. Some 62 million tons of electronic waste was generated in 2022 and that figure is on track to reach 82 million tons by 2030, the report said. It said only 22% of the waste was properly collected and recycled in 2022 and that quantity is expected to fall to 20% by the end of the decade due to higher consumption, limited repair options, shorter product life cycles, and inadequate management infrastructure.