Japan has begun releasing treated radioactive water from the Fukushima plant into the Pacific Ocean - 12 years after a nuclear meltdown.
The UN's atomic regulator says the discharge is safe and will have "negligible" impact on humans and the environment.
But China has slapped a ban on Japanese seafood - and there have been protests in Japan and South Korea.
Japan says it has filtered the water to one main radioactive isotope - tritium can't be removed from water so it has been diluted.
The limit for tritium in the Fukushima water is 1,500 becquerel/litre - six times less than the World Health Organization's limit for drinking water.
Experts also say there is no scientific evidence backing concerns around seafood, as the radiation released is so low.