Where do your computers, tablets and smartphones go to die? Electronic waste is an environmental problem throughout Asia, but nowhere more so than in Hong Kong. For a long time the city was only a stepping stone before the waste went to mainland China. But since 2015, the Chinese authorities have banned its import and containers remain docked. Clandestine landfills are now popping up in Hong Kong. Our correspondents Antoine Védéilhé, Vivien Wong and Sarah O'Meara report on the consequences.