Only 3 countries have never stopped transmission of polio: Pakistan, Afghanistan and Nigeria, largely because conflicts and cultural opposition thwart vaccination efforts. A common perception in Pakistan is that polio vaccination teams face difficulties only in tribal or rural areas, but there are equally big challenges in the country's cities, such as Lahore, the country's second most populous city. More in this report from Saman Khan in Lahore. VOA's Bezhan Hamdard narrates.
