"Japan to release over 1 million tonnes contaminated Fukushima water into sea after treatment"
Japan has approved a plan to release more than one million tonnes of contaminated water from the destroyed Fukushima nuclear plant into the sea.
The water will be treated and diluted so radiation levels are below those set for drinking water.
But the local fishing industry has strongly opposed the move, as have China and South Korea.
Tokyo says work to release water used to cool nuclear fuel will begin in about two years.
The final approval comes after years of debate and is expected to take decades to complete.
Reactor buildings at the Fukushima power plant were damaged by hydrogen explosions caused by an earthquake and tsunami in 2011. Three reactors overheated and partly melted in the days that followed.
More than a million tonnes of water has been used to cool the melted reactors.
Currently, the radioactive water is treated in a complex filtration process that removes most of the radioactive elements, but some remain, including tritium - deemed harmful to humans only in very large doses.
It is then kept in huge tanks, but the plant's operator Tokyo Electric Power Co (Tepco) is running out of space, with these tanks expected to fill up by 2022.
About 1.3 million tonnes of radioactive water - or enough to fill 500 Olympic-sized swimming pools - are currently stored in these tanks, according to a Reuters report.
Environmental groups like Greenpeace have long expressed their opposition to releasing the water into the ocean.
The NGO said Japan's plans to release the water showed the government "once again failed the people of Fukushima".
The country's fishing industry has also argued against it, worried that consumers will refuse to buy products from the region.
The decision has also prompted criticism from Japan's neighbours. Ahead of the decision, South Korea's foreign minister on Monday expressing "serious regret".
Chinese foreign ministry spokesman Zhao Lijian also urged Japan to "act in a responsible manner".
The US appears to support Japan's decision, however, saying it seemed to have "adopted an approach in accordance with globally accepted nuclear safety standards".
Japan argues that the release of the wastewater is safe as it is processed to remove almost all radioactive elements and will be greatly diluted.
Scientists argue that the elements remaining in the water are only harmful to humans in large doses. With dilution, the treated water poses no scientifically detectable risk, they say.
"What happened in Fukushima"
On 11 March 2011, a 9.0 magnitude earthquake struck off the north-eastern coast of Japan, triggering a 15-meter tsunami.
While the backup systems to prevent a meltdown at the Fukushima nuclear plant survived the initial quake, further damage was inflicted by the tsunami.
As the facility's cooling systems failed in the days that followed, tonnes of radioactive material was released. The meltdown was the worst nuclear accident since Chernobyl in 1986.