The operator of the crippled Fukushima Daiichi nuclear power plant said Friday it started releasing a fifth batch of treated radioactive water into the sea from the plant, amid opposition from China, Paralel.Az reports citing Kyodo.

Tokyo Electric Power Company Holdings Inc. will discharge 7,800 tons of water through May 7 in the first discharge of the current fiscal year, which began this month.

Before releasing water, TEPCO ensures the radioactivity levels meet the standards set by itself and the government.

The utility plans to discharge a total of about 54,600 tons on seven occasions this fiscal year. Tritium levels are expected to be kept to around 14 trillion becquerels, below the annual cap of 22 trillion becquerels.

The water is being treated using an advanced liquid processing system, or ALPS, to remove most of the contaminants other than the relatively nontoxic tritium.

Since the start of the operation on Aug. 24 last year, about 31,200 tons have been released despite opposition from China, Russia and local fishermen due to concerns over safety, health issues and tarnishing the reputation of local seafood.

China has kept an import ban in place on all seafood products from Japan in response to the discharges.

During the release of the previous four batches, TEPCO said it detected up to 22 becquerels of radioactive tritium per liter of seawater in samples taken from areas near the power complex, far below the World Health Organization's limit of 10,000 becquerels for drinking water.

The utility sees the discharge as a key step in the ongoing decommissioning of the Fukushima Daiichi plant, which suffered fuel meltdowns in three reactors following a massive earthquake and tsunami in 2011.