In Mumbai, four employees of an industrial plant died and 10 people took ill following leakage of gas at the Tarapur Industrial Estate in Boisar Tuesday night. According to police, hydrogen sulfide gas leaked at around 7.30 pm yesterday from a plant belonging to Sequent Scientific Limited.Those who took ill were taken to a private hospital and treated. The leakage was plugged and a rescue team rushed to the factory for relief operations.