The Sensex at the Bombay Stock Exchange shot up a massive 491 points, or 2.5 percent, to close at a 28-month high of 20,213, today, after the Reserve Bank said that the low inflation numbers will be taken into account in its next monetary policy review. The Nifty at the National Stock Exchange spurted 151 points, or 2.5 percent, to 6,147.Stock markets in Japan, China, Hong Kong, South Korea and Singapore gained between 0.1 percent and 2.3 percent.