The Sensex at the Bombay Stock Exchange fell 57 points, or 0.3 percent, to 20,876, after another session of choppy trade, on profit-booking and amid weak global cues, today. The Nifty at the National Stock Exchange lost 26 points, or 0.4 percent, to 6,276.Stock markets in Japan, China, Hong Kong, South Korea and Singapore ended mixed.