Falling for the sixth straight session, the Sensex at the Bombay Stock Exchange declined 162 points, or 0.9 percent, to close at a nearly two-month low of 18,309, on fag-end selling by investors, today. The Nifty at the National Stock Exchange fell 57 points, or 1 percent, to 5,574.Stock markets in Japan, China, Hong Kong, South Korea and Singapore ended mixed.