The Bombay Stock Exchange benchmark Sensex today opened 57 points higher. The 30-share index, which had lost 44.52 points in the previous session, rose by 57.10 points, or 0.29 per cent, to 20,072.90 points.Likewise, the wide-based National Stock Exchange Nifty index moved up by 22 points, or 0.20 per cent, to 6,006. In Asia, Hong Kong's Hang Seng index was up 0.26 per cent in early trade, while Japan markets were closed today in observance of a national holiday. In the US, the Dow Jones Industrial Index had ended 0.23 per cent higher yesterday.