Ahmedabad, June 8 -- Four workers died after allegedly inhaling toxic gases while cleaning an underground effluent treatment plant (ETP) tank at a jewellery manufacturing unit in Surat on Sunday, police said. Surat Police Commissioner Anupam Singh Gehlot said an FIR had been registered for causing death due to negligence. He added that one body had been handed over to the family, while three were at the hospital mortuary. He said the company owner was in Mumbai and on the way to Surat. The incident took place at Rati Jewellers, a jewellery manufacturing unit near Choryasi Dairy in the Ashwini Kumar area, during a routine cleaning operation of the underground tank. Police said the four workers, including a supervisor, entered the tank and so...