Falling for the third straight session, the Sensex at the Bombay Stock Exchange declined 247 points, or 1.4 percent, to a more than six-week low of 17,693, amid a rise in food inflation, and weak global cues on Thursday. The Nifty at the National Stock Exchange lost 73 points, or 1.4 percent, to 5,332.Stock markets in Japan, China, Hong Kong, Singapore, and South Korea ended largely lower.