The BSE benchmark Sensex fell by 163 points in the early trade today on fresh selling by funds amid a weak trend on other Asian bourses.The wide-based National Stock Exchange index Nifty declined by 48.25 points to 5,311.15 points.In Asian, the Hong Kong's Hang Seng index fell by 0.18 per cent, while Japan's Nikkei was down by 0.21 per cent higher in the early trade today.