Falling for the second straight session, the Sensex at the Bombay Stock Exchange dropped 154 points, or 0.8 percent, to 18,174, today. Slower factory output , high crude oil prices, and weak global markets weighed are said to be the cause for the fall. The Nifty at the National Stock Exchange shed 49 points, or 0.9 percent, to 5,445.Stock markets in Japan, China, Hong Kong, Singapore and South Korea fell between 0.8 percent and 1.7 percent.