Tokyo residents were warned not to give babies tap water because of radiation leaking from a nuclear plant crippled in the earthquake and tsunami that devastated northeast Japan in the world's costliest natural disaster. The U.N. atomic agency said there had been some positive developments at the Fukushima nuclear plant [owned by Tokyo Electric Power Co (TEPCO)]...but the overall situation remained serious...Tokyo authorities said on Wednesday that water at a purification plant for the capital...had 210 becquerels of radioactive iodine -- more than twice the safety level for infants. Tokyo Governor Shintaro Ishihara said that level posed no immediate risk. "But, for infants under age one, I would like them to refrain from using tap water to dilute baby formula."...Physicians for Social Responsibility, a U.S. anti-nuclear group, disputed the food safety assurances and called for a more strict ban on sales of exposed food.