A nation-wide anti-polio drive began today (Monday) to administer vaccine to children under five years of age. Polio teams comprising health department officials will go door to door to administer polio drops. In the Punjab, during the week-long campaign, more than 23 million children will be administered anti-polio drops. The health department has declared Lahore, Faisalabad and Multan as the most sensitive cities in this regard.