The benchmark index of the Indian equities market closed lower on Monday with the 30-scrip sensitive index of the Bombay Stock Exchange, Sensex, closing at 18540.89 points, 233.35 points or 1.24 percent lower from the previous close of 18774.24 points. The Sensex had a turnover of 5.39 billion rupees (about 91.31 million U.S. dollars).