I think the most difficult problem about Japanese is that leak of radiation will affect their health. Because the radioactive material will make people have cancer and die easily. And they will not have enough water because the water will be polluted. So Japanese cannot drink the water. If they drink the polluted water, they may have cancer.
I think Japanese government can find other suitable governments to offer water and Asians can donate water to them. Now some of the water from Asian and Asia Brewery in the Philippines has pledged to send 700,000 bottles of water to Tokyo. It is good for them to solve the problem.