Snapping a three-day winning streak, the Sensex at the Bombay Stock Exchange fell 151 points, or 0.8 percent, to 19,648, on profit-booking, and on weak Asian and European markets, today. Investors also turned cautious ahead of the Reserve Bank's monetary policy review, tomorrow. The Nifty at the National Stock Exchange fell 52 points, or 0.9 percent, to 5,892. Stock markets in Japan, China, Hong Kong and Singapore lost between 0.1 percent and 2 percent.