LAHORE: At least four children were killed and 20 people were injured after the roof of a classroom at a private school in Punjab’s Dera Ghazi Khan collapsed on Thursday. The preliminary report of the incident released by the district administration confirmed the number of casualties. The injured include 16 students, two teachers and as many labourers, according to the report, seen by Dawn. It said the incident was reported around noon, following which rescue personnel and ambulances were sent t