Erasing early gains of about 195 points, the BSE benchmark Sensex was trading 70 points or 0.40 per cent down at 17,607 points a shortwhile ago. It rose by over 82 points in early trade today. The 30-share barometer, fell by 243 points in the previous session. The wide-based National Stock Exchange Nifty index was also trading 20 points, or 0.37 per cent down at 5,360 points .