Snapping a four-day winning streak, the Sensex at the Bombay Stock Exchange dropped 37 points, or 0.2 percent, to close at 19,646, on Monday, on mild profit-booking by investors ahead of industrial and inflation data, and amid weak European markets. The Nifty at the National Stock Exchange lost 3 points, to 5,942.Stock markets in Japan, China, Hong Kong, South Korea and Singapore ended mixed.