Even as it blocks deliveries of food and other crucial aid, the Syrian government allows the Syrian Arab Red Crescent through its siege lines into rebel-held areas to immunize children against polio. A Syrian Arab Red Crescent volunteer administers polio vaccine to a young girl in the rebel-held Damascus suburb of Yelda. A Syrian Arab Red Crescent volunteer administers polio vaccine to a young girl in the rebel-held Damascus suburb of Yelda.