The Sensex, at the Bombay Stock Exchange surged 339 points or 1.9 percent to close at 18,560. The Nifty of the National Stock Exchange, advacned 98 points or 1.8 percent to 5,577. In the broader market, on the BSE, the Midcap index gained 1.3 perent and the Smallcap index added 1.8 percent.