The Sensex at the Bombay Stock Exchange had fallen 66 points, or 0.4 percent, to 18,604, when reports last came in, during a special, 75 minute, muhurat trading session from 3.45 p.m. to 5 p.m., today. The Nifty at the National Stock Exchange had declined 23 points, or 0.4 percent, to 5,661.