The benchmark Sensex fell for the fourth day today losing 230 points due to heavy selling by investors . The Bombay Stock Exchange barometer, settled at 16.052.points, a loss of 230 points over the previous close. Earlier in the day, the 30-share index had dipped below crucial 16,000 points level. The wide-based National Stock Exchange index Nifty dipped by 75.60 points to close at 4,750 points.