Snapping three days of gains, the Sensex at the Bombay Stock Exchange declined 256 points, or 1.2 percent, to close at 20,635, on profit-booking by investors, amid cautious global markets, today.

The Sensex had rallied almost 700 points in the previous three trading sessions. The Nifty at the National Stock Exchange dropped 80 points, or 1.3 percent, to 6,123.

Stock markets in Japan, China, Hong Kong, South Korea and Singapore ended mixed.