The BSE benchmark Sensex fell 52 points to 17,413 in opening trade today, extending its three-day losing streak. This follows weak cues from Asian markets amid fears that the euro zone debt crisis will worsen. The 30-share Sensex, which has lost nearly 340 points over the past three sessions, fell by 0.30 per cent, with metal, oil and gas, auto and banking stocks leading the fall.In a similar fashion, the wide-based National Stock Exchange Nifty index shed 17.85 points, or 0.34 per cent, to 5,241.In the Asian region, Hong Kong's Hang Seng index was down by 2.42 per cent in early trade today, while Japan's stock market was closed for a national holiday. The Dow Jones Industrial Average in the US closed 1.53 per cent higher in Wednesday's trade.