A UN watchdog has said that Japan"s plan to release wastewater from the tsunami-wrecked Fukushima nuclear plant into the sea complies with international standards. The International Atomic Energy Agency says the release will have a "negligible" impact on the environment. The Fukushima facility is running out of storage space for the water, which was used to cool nuclear reactors. Japan"s plan has been opposed by China and South Korea. Tokyo has not announced a schedule for the release and the plan still needs approval from a regulator. In 2011, a tsunami triggered by a magnitude 9.0 earthquake flooded three reactors of the Fukushima Daiichi Nuclear Power Plant. It is regarded as the world"s worst nuclear disaster since Chernobyl. More than 150,000 people were evacuated from an exclusion zone around the plant, which remains in place. Decommissioning of the plant has also started, but the process could take decades. IAEA chief Rafael Grossi released the findings of a two-year safety review on Tuesday and vowed to continue engaging with Japan after the water is discharged. In May, the agency said that national nuclear regulator Tokyo Electric Power (Tepco) had shown its ability to make "accurate and precise measurements" of the amount of radiation present in the treated water. A final approval from Tepco could come as early as this week. The plant produces 100 cubic meters of wastewater daily. Tanks on site can hold 1.3 million cubic meters. Most radioactive elements have been filtered from the water, except for tritium, an isotope of hydrogen that is difficult to separate from water. Tokyo has said the water that will be released into the Pacific Ocean, which has been treated with seawater, has tritium levels well below internationally approved levels. Nuclear power plants around the world regularly release wastewater with tritium levels above that of the treated water from Fukushima. But the IAEA"s findings will do very little to ease the concerns of the Japanese public and neighboring countries. China had already strongly criticized Japan"s plan and warned the IAEA against endorsing it. South Koreans, on the other hand, have stocked up on sea salt ahead of the water"s release, amid food safety fears. Local fishing communities have also fiercely objected, saying it will cause further damage to their reputation. —BBC