Japan has begun pumping out treated water from the Fukushima nuclear plant into the Pacific Ocean, 12 years after the meltdown at the site.
The UN’s atomic regulator said the discharge met safety standards and would have a “negligible” impact on humans and the environment.
But the decision has prompted concern in China, South Korea and the Pacific islands – with Hong Kong and Macau imposing bans on Japan’s seafood.
Japan says it has filtered the water to one main radioactive isotype – tritium can’t be removed from water so will be diluted.
The tritium limit of the Fukushima water will be 1,500 becquerel/litre – six times less than the World Health Organization’s limit for drinking water.
The discharge began at 13:00 local time (0500 BST), with the water piped through an underwater tunnel.