Salt Lake has reverted to the high-iron content ground water after the state government's assurance of providing 50 lakh gallons of sweet water from Tallah-Palta turned out to be virtually a hoax. The daily supply of sweet water to Salt Lake has dropped to a low of about 20 kah gallons, leaving a huge gap of about 30 lakh gallons, calling for immediate ground water utilisation to pre-empt residents' unrest.