TOKYO (AP) — The Japanese government announced Tuesday the treated and diluted radioactive wastewater from the Fukushima Daiichi nuclear power plant will be released into the ocean as early as Thursday.

Prime Minister Fumio Kishida gave the final go-ahead at a meeting of Cabinet ministers involved in the plan and instructed the operator, Tokyo Electric Power Company Holdings, to be ready to start the release Thursday if weather permits.

The water release begins nearly 12 and half years after the March 2011 nuclear meltdowns caused by a massive earthquake and tsunami.

Japanese fisheries groups have opposed the plan out of worry of further damage to the reputation of their seafood. Groups in China and South Korea have also raised concern, making it a political and diplomatic issue.

The government and TEPCO say the water must be released to make room for the plant’s decommissioning and to prevent accidental leaks.

They say the treatment and dilution will make the wastewater safer than international standards and its environmental impact will be negligibly small. But some scientists say long-term impact of the low-dose radioactivity that remains in the water needs attention.