MUMBAI: Dalal Street witnessed heightened volatility on Monday with the sensex swinging over 1,200 points from a sharp rally in the first few minutes to a sudden dive below the previous close and finally settling in the red.In early trade, the indices rallied on the back of RBI’s weekend measures to support the rupee-which gained over Re 1 in early trades-but they gave up those gains by mid-session. Sensex lost 548 points to close at 71,925 points while Nifty was down 157 points at 22,364 points. Smallcap and midcap stocks, however, witnessed some buying interest.The day’s slide in the market came on the back of a Rs 1,708-crore net foreign fund outflow, while domestic funds were net buyers at Rs 3,045 crore, BSE data showed. At close, investors’ wealth was up by a marginal Rs 14,000 crore to Rs 365.5 lakh crore.