At the interbank foreign exchange market, the rupee sank by a staggering 109 paise, or 1.9 per cent, to a life-time closing low of 58.15 against the dollar on Monday. A confluence of negative factors, including heavy dollar demand, and slowdown in capital inflows put pressure on the rupee, which has slumped by 8 per cent, from a level of 53.80 rupees to the dollar on April 30. Forex traders said there were no visible signs of Reserve Bank intervention to arrest the rupee slide.