The Sensex at the Bombay Stock Exchange fell 150 points, or 0.8 percent, to close at a nearly one-month low of 19,610, amid weak global markets on Monday. The Nifty at the National Stock Exchange dropped 47 points or 0.8 percent, to 5,939. Stock markets in Japan, China, Hong Kong, South Korea and Singapore declined between 0.1 percent and 3.7 percent.