The Sensex fell by almost 64 points in opening trade today. The 30-share barometer fell by 63.92 points, or 0.34 per cent, to 20,245.77 points at the start of trade, with realty, capital goods, and banking and technology sector stocks leading the fall.Similarly, the wide-based National Stock Exchange Nifty index also declined by 21 points, or 0.35 per cent, to 6,199 points.In other Asian markets, Hong Kong's Hang Seng index was trading lower by 0.39 per cent, while Japan's Nikkei was up by 0.60 per cent in early trade today.The US Dow Jones Industrial Average had ended 0.08 points higher in Monday's trade.