Falling for the fourth straight session, the Sensex at the Bombay Stock Exchange lost 140 points, or 0.7 percent, to close at 19,451 today. The Nifty at the National Stock Exchange dropped 44 points, or 0.7 percent, to 5,842.Stock markets in Japan, China, Hong Kong, South Korea and Singapore gained between 0.3 percent and 1.9 percent.