Snapping three days of losses, the Sensex at the Bombay Stock Exchange surged 213 points, or 1.1 percent, to trade at 20,430, in the afternoon session, a short while ago, on buying by funds amid firm Asian markets. The Nifty at the National Stock Exchange advanced 66 points, or 1.1 percent, to 6,061.In other Asian markets, key benchmark indices in Japan, Hong Kong, Singapore, South Korea, Taiwan and Indonesia gained between 0.1 percent and 1.5 percent, in intra-day trade.