Japan has begun discharging treated waste water from the Fukushima nuclear plant into the Pacific Ocean.

The move has stirred controversy, sparking protests in the region and retaliation from Beijing.

China is the biggest buyer of seafood from Japan – on Thursday it said it would block all such imports.

Japan maintains that the water is safe and there has been agreement from a number of scientists and the UN’s nuclear watchdog.

Since a tsunami destroyed the Fukushima nuclear plant in 2011, water has been pumped to cool down the reactors’ fuel rods.

BBC News says the plant produces contaminated water every day, which is treated and stored in massive tanks.

More than 1,000 tanks have been filled, however Japan says this is not a sustainable long-term solution.

It argued that after treatment and dilution, the water is safe to release.

More than a million tonnes of water stored at the nuclear plant will be discharged over the next 30 years.

Authorities have also promised to continuously monitor levels of radiation in the ocean and maintain a high level of transparency.

(Photo Credit: Tokyo Electric Power Co.)