THANE, Feb. 18 -- The slab of a fifth-floor apartment in Thane's Wagle Estate collapsed onto the flat below in the early hours on Tuesday, injuring three people, one of whom is critical. The building was earlier classified by the Thane Municipal Corporation (TMC) as a C2B structure, indicating it required major structural repairs, but was not immediately dangerous. After the slab collapse incident around 3am on Tuesday, officials surveyed the building and determined that it poses significant risk. Accordingly, all residents were shifted elsewhere and the building may be pulled down after further assessment, officials said. The incident occurred at Nutan Neelam Apartment, a 30/35-year-old five-storeyed building in the Shanti Nagar locality of Wagle Estate. Residents were asleep when the slab from flat 501, owned by Gajendra Prasad, 60, suddenly gave way and crashed into flat 401, owned by Prince Yadav, 25. Owners of both flats and Pradeep Yadav, Prince Yadav's relative, who were injured, were rushed to the government-run Matoshree Gangubai Shinde Hospital nearby. Since Pradeep Yadav suffered severe injuries including multiple fractures in his legs, he was later referred to Fortis Hospital for advanced treatment. Sources in Fortis Hospital said his condition was critical. Yasin Tadvi, chief of TMC's disaster management cell said multiple emergency teams including disaster management, fire brigade, public works department (PWD), and power supply were rushed to the site for rescue operations. The building comprises A and B wings with a total of 26 flats, and around 80-85 residents were found residing there at the time of rescue, Tadvi noted, adding, "All of them have been evacuated - around half have been shifted temporarily to a nearby municipal school while others have made alternative arrangements on their own." The disaster management cell chief said the building had been sealed to prevent unauthorised entry and ensure public safety. "Officials from TMC's public works department will conduct further structural evaluation, and necessary action including possible demolition and relocation of residents will be undertaken in the coming days," Tadvi said. In a separate incident on Sunday, a senior citizen identified as Prema Bhosle, 58, sustained injuries to her hands and legs after a portion of the plaster from the fifth-floor ceiling crashed into her flat below at Ayodhya Complex in Kisan Nagar, Thane....