The Sensex at the Bombay Stock Exchange surged 337 points, or 2 percent, to again regain the 17,000 level, at 17,085, as investors bought stocks at lower levels, and amid rising European markets on Wednesday.The Nifty at the National Stock Exchange jumped 102 points, or 2 percent, to 5,139.Stock markets in Japan, China, Hong Kong, Singapore, and South Korea ended mixed.