The Sensex at the Bombay Stock Exchange rallied 217 points, or 1.2 percent, to 18,440, on Tuesday, on renewed buying by investors, amid falling crude oil prices, and positive regional bourses. The Nifty at the National Stock Exchange rose 58 points, or 1.1 percent, to 5,521. Stock markets in Japan, China, Hong Kong, South Korea and Singapore rose between 0.1 percent and 1.7 percent.