Snapping five days of gains, the Sensex at the Bombay Stock Exchange declined 265 points, or 1.3 percent, to close at 20,975, on profit-booking by investors, today. The Sensex had climbed almost 670 points in the previous five trading sessions. The Nifty at the National Stock Exchange fell 64 points, or 1 percent, to 6,253. Stock markets in Japan, China, Hong Kong, South Korea and Singapore ended mixed.