Japan is set to begin releasing treated radioactive wastewater from its Fukushima nuclear plant into the Pacific Ocean on Thursday (August 24), amid strong opposition from several countries.
The plan has been in the works for years, with authorities warning in 2019 that storage space was running and that they had "no other options" but to release it.
While some countries have expressed support for Japan, others have been outspoken in their opposition to the wastewater release, with many consumers in Asia stockpiling salt and seafood in anticipation of future contamination.
Here's what we know so far.
Fukushima water: When and how will it be released?
On Tuesday, Japanese Prime Minister Fumio Kishida said that the government had formally decided to start releasing the water as early as Thursday, August 24, "if they encounter no obstacles."
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Over the years, the wastewater has been continually treated to filter out all the removable harmful elements, then stored in tanks. Much of the water is treated a second time, said state-owned electricity firm Tokyo Electric Power Company (TEPCO).
When the wastewater is finally released, it will be heavily diluted with clean water, resulting in very low concentrations of radioactive material. It will travel through an undersea tunnel about one kilometre (0.62 miles) off the coast into the Pacific Ocean.
Third parties, including the United Nations' nuclear watchdog, the International Atomic Energy Agency (IAEA), will monitor the discharge during and after its release.
Meanwhile, the IAEA has personnel stationed in a newly-opened Fukushima office and will monitor the situation for years to come.
Why is Japan releasing water from the Fukushima nuclear plant?
The devastating 2011 Tohoku earthquake and tsunami damaged the Fukushima nuclear plant's power supply and cooling systems, causing the reactor cores to overheat and contaminate water within the plant with highly radioactive material.
Since then, new water has been pumped in to cool fuel debris in the reactors. At the same time, groundwater and rain have leaked in, resulting in more radioactive wastewater that needs to be stored and treated.
TEPCO built massive tanks to contain the wastewater, but space is quickly dwindling. The company claims that building more tanks isn't an option and needs to free up space to safely decommission the plant.
In a July interview with CNN, IAEA Director General Rafael Grossi stated that Japan had evaluated five methods for getting rid of the water, including vapour release, which would have included boiling wastewater and releasing it into the atmosphere.
However, the majority of these options are "considered industrially immature," he said.
What are the risks of releasing treated radioactive water?
TEPCO claims that while radioactive wastewater contains certain harmful elements, the majority of these can be eliminated through various treatment processes.
The underlying problem is that there is no mechanism to remove a hydrogen isotope called radioactive tritium, and authorities and experts are divided on the risk it poses, if any.
TEPCO, Japan's government, and the IAEA claim that tritium exists naturally in the environment, including in rain and tap water, and that the wastewater is safe, especially given that it would be released gradually over decades.
However, some scientists are concerned that even diluted wastewater could harm marine life and pollute the already fragile ecology.
Mixed reaction over Japan's nuclear wastewater plan
The plan has received mixed reactions, with some supporters and others sceptical.
The US has backed Japan, and nearby Taiwan has agreed that the quantity of tritium being released should have a "minimal" impact.
On the other hand, China and the Pacific Islands have been vocal in their objection, arguing that the release could have far-reaching regional and international impact, including endangering human health and the marine ecosystem.
Some governments have even banned food imports from parts of Japan, including Fukushima.
While South Korean leaders have overwhelmingly backed the plan, opposition politicians have expressed concern, and protesters have called for it to be stopped.
Public concern has also grown, with seafood enthusiasts in mainland China, Hong Kong, and others pledging to stop eating Japanese products once the wastewater is released. Some consumers have loaded up on sea salt and other commodities such as seaweed and anchovies, fearing contamination.
The blowback has worried fishing communities in Japan and South Korea, who say this could mean the end of their livelihoods, particularly in Fukushima, where the fishing industry is now worth just a fraction of what it once was before the 2011 disaster.