NAVI MUMBAI, March 6 -- A 13-year-old boy died and 11 other children were injured after a portion of a building slab collapsed onto a ground-floor tuition class in Kopar Khairane on Thursday evening. Civic officials said the accident occurred between 4.30 pm and 5 pm at flat number 2 on the ground floor of Vidyabhavan Apartment in Sector 2. The teacher, Shyamali Choudhary (53), sustained minor injuries and was discharged after primary treatment. Navi Mumbai Municipal Corporation said 11 students were inside the flat at that time. Officials said a probe is on. htc...