Sales of domestically produced seafood have surged dramatically on Chinese e-commerce platforms, which have vowed to step up testing for radioactive substances to ensure the safety of these products, after Japan started releasing nuclear-contaminated water into the ocean on Thursday.

People in Tokyo were largely supportive after Japan said on Tuesday it would start releasing more than one million metric tonnes of treated radioactive water from the wrecked Fukushima nuclear power plant in the coming days, putting into motion a plan that has drawn strong criticism from China.