Falling for the third straight session, the Sensex at the Bombay Stock Exchange ended with a slim loss of 21 points, or 0.1 percent, at 19,591, today, on continued selling pressure, amid high global crude oil prices. The Nifty at the National Stock Exchange dropped 6 points, or 0.1 percent, to 5,886.Stock markets in Japan, China, Hong Kong, South Korea and Singapore again ended mixed.