Japan put into action today its controversial plan to dump used and then treated water from the damaged Fukushima Daiichi nuclear power plant in northeastern Japan into the Pacific Ocean, TEPCO, the company that runs the facility, said.

The pumps were activated and the valves were opened for the waters to reach the sea.

These waters have been treated in order to clean them of most radioactive substances, but it was not possible to filter out tritium, which, however, is not considered dangerous for human health except in large concentrations.

The process is described as safe and harmless by Japanese authorities and the International Atomic Energy Agency (IAEA), which took over the task of overseeing the project and gave the go-ahead in July.

However, it causes strong reactions from environmental protection organizations, Japanese fishermen, as well as governments of countries in the region, especially China.