The BSE benchmark index Sensex, which fell by over 70 points in the early trade today, lost further ground in late morning deals and was trading 221 points in the negative territory at 17,703, when reports last came in. After losing over 500 points in the previous three sessions, the 30-share index fell by 70 points, or 0.39 per cent, to 17,853 points in the early trade today. The wide-based Nifty of the National Stock Exchange was trading 77 points down at 5,352.