Kolkata, Feb 21 (PTI) Bill Gates, Co-chairperson of the Bill and Melinda Gates Foundation today praised West Bengal Chief Minister Mamata Banerjee for her government's efforts to eradicate polio. "It is with utmost pleasure that I congratulate you on achieving a full year without polio. A historic milestone not only in India, but also for the whole world," Gates said in a letter to Mamata. "Your popularity as a people's leader can help overcome community resistance to vaccination and address migrant population which are at highest risk for being under immunised," Gates said.