4 migrants choke to death in water tank at bldg site in Nagpada. One worker was injured while attempting a rescue. The tank had been shut for two years, leading to accumulation of sludge and toxic gases due to past chemical treatments. Workers at the site said it was common practice to step into water tanks without safety gear, but none of them was aware of the hazardous conditions inside this particular tank. They should have left the tank open for a while to let the gases escape, said Bhutan Sheikh, who was injured in the incident. At the time of going to press, police were in the process of registering four accidental death cases. An FIR may be lodged if police find negligence on the part of the builder. “We are questioning the labour contractor. We are summoning all individuals concerned ,” said a police officer. The 40-plus-storey building is being built in the central area of the city and is expected to be completed by the end of the year.