Hong Kong environmental authorities have asked the Malaysian government to provide details on nine containers of plastic waste it sent back to the city. This came as local environmental groups demanded on Wednesday that the city government revamp and tighten plastic waste import policies. Earlier this week, the Southeast Asian government said it had returned 150 containers of plastic waste, weighing 3,737 tonnes, to 13 places of origin since the third quarter of last year. Nine containers have been returned to Hong Kong, while others were sent to France, Britain, the US and elsewhere. The containers returned to Hong Kong were labelled as recyclable plastics, but did not have permits to enter Malaysia. The Malaysian government suspected the waste had been contaminated. Kate Lin Pui-yi, Greenpeace Hong Kong’s senior campaigner, said the waste should be sent on to its country of origin if it was discovered Hong Kong had originally re-exported it. “If Hong Kong was only the re-exporter of the nine containers, then they should be sent back to the country of origin,” she said. “But if the waste was indeed exported from Hong Kong, it should be sent back here. “But more importantly, in the long term, this waste should be banned from entering the city.” Green groups estimate that in 2018 Hong Kong re-exported 280,000 tonnes of plastic waste worth HK$727 million (US$93 million) from the US, Japan, Germany, Britain and Mexico, to countries such as Thailand, Malaysia and Vietnam. More than 17 million pieces of plastic waste flushed into sea via Hong Kong’s Shing Mun River each year Hong Kong has become one of the biggest re-exporters of plastic waste after mainland China stopped importing waste two years ago. Other countries that have traditionally imported the waste, including Malaysia and the Philippines, have become reluctant to accept any more. Such waste is usually exported from developed countries to developing nations, where traders then pick out items to be recycled for a profit. According to amendments to the Basel Convention, an international treaty that covers Hong Kong, waste traders will from January 2021 need the consent of the importing countries for the export of mixed, non-recyclable and contaminated plastic waste. But Lin said the Hong Kong government did not have to wait for another year and could just decide right now to ban the imports. She was concerned some waste would be dumped in the city’s landfills. On Wednesday, the Environmental Protection Department said Hong Kong would not accept any waste containers that had not originated in the city, and that it was “contacting the relevant authority of Malaysia to request for more information” on the nine returned consignments. A spokesman added that last year 12 containers of plastic recyclables were sent back to Hong Kong because no party accepted the shipments at the receiving end. “The concerned exporters finally sent the plastic recyclables to local recycling facilities in Hong Kong or re-exported to other places for recycling. There is no evidence suggesting that the concerned shipments involved illegal exports,” he said. He added the government “fully commits” to joining the global efforts under the Basel Convention. “The import and export of recyclables, including waste plastics, are allowed only if the shipment is uncontaminated and imported or exported for the purpose of reprocessing, recycling, recovery or reuse,” he said. Edmond Lau Shiu-long, project officer at environmental group The Green Earth, suggested the government should only allow containers of waste that could largely be recycled to be brought to Hong Kong. Lau’s colleague, executive director Edwin Lau Che-feng, urged authorities to conduct more frequent inspections of the containers, to ensure they carry the items that are declared to the Customs and Excise Department. Dr Chung Shan-shan, a Baptist University expert specialising in waste management, said the head of the Environmental Protection Department had the power to stop plastic waste from entering, if he believed it to be contaminated. China's recycling revolution: How the National Sword policy caused global disruption However, there is no clear definition of “contamination” under the law, meaning it is subject to different interpretations, she added. This mechanism, which gives the department head the power to make a decision, allowed the government flexibility in handling different situations, Chung said. She did not agree that waste imported to Hong Kong would easily end up in landfills, as traders would need to pay hefty sums to the government to dump it there.