Rising for the fourth straight session, the Sensex at the Bombay Stock Exchange gained 143 points, or 0.7 percent, to end a shade below the 20,000 mark, at 19,993, today, on easing food inflation, and amid firm global markets. During the day, the Sensex had touched a high of 20,084 points. The Nifty at the National Stock Exchange rose 51 points, or 0.9 percent, to 6,012.Elsewhere, stock markets in Japan, China, Hong Kong, South Korea and Singapore rose between 0.5 percent and 2 percent, as worries about Europe's debt problems eased.