Rising in tandem with global markets, the Sensex at the Bombay Stock Exchange zoomed 516 points–its biggest single-day gain in two months–to close at a three-month high of 17,805, today, on heavy buying in blue-chips, as the euro-zone debt crisis eased. The Nifty at the National Stock Exchange jumped 159 points, or 3.1 percent, to 5,361.Stock markets in Japan, China, Hong Kong, Singapore and South Korea gained between 0.5 percent and 2 percent.