Japan released wastewater from its Fukushima nuclear plant for a second day despite criticism from China and protests by angry citizens at home.
Japan began releasing wastewater from its Fukushima nuclear plant into the Pacific Ocean on Thursday, prompting China to ban all seafood imports from its neighbour.
The start of the discharge of water, equivalent to about 540 Olympic swimming pools over several decades, is a big step towards decommissioning the site 12 years after one of the world's worst nuclear accidents.
The water has been treated and according to the operator TEPCO, there is no health risk.
The operation has been endorsed by the International Atomic Energy Authority (IAEA). The group said on Thursday that new on-site tests had confirmed the levels of radioactive tritium in the water being discharged were safe.
However, their arguments have not convinced many people in the country. Dozens of protesters demonstrated in Toyko on Friday to condemn the move.
One objector, Kenicho Sato, said: "It's like dumping an atomic bomb in the ocean. Japan is the first country that was attacked with an atomic bomb in the world, and the prime minister of the country made this decision."
Environmental group Greenpeace has said the filtration process is flawed. China and Russia have suggested the water be vaporised and released into the atmosphere instead.
However many experts insist the operation is safe. Tom Scott from the University of Bristol said: "When released into the Pacific, the tritium is further diluted into a vast body of water and would quickly get to a radioactivity level which is not discernibly different from normal seawater."