Fukushima: Water pouring down from hills
23 August 2013 Last updated at 07:23 BST
Japan's nuclear watchdog has said the crippled Fukushima nuclear plant is facing a new "emergency" caused by a build-up of radioactive groundwater.
In the mountains above the crippled Fukushima nuclear plant, rainfall collects and flows down to the Pacific - through highly contaminated ground.
The Nuclear Regulatory Authority says a barrier built to prevent that water reaching the ocean has already been breached, while tanks built to contain it are nearly full.
Rupert Wingfield-Hayes reports from Fukushima.