The Sensex at the Bombay Stock Exchange dropped 163 points, or 1 percent, to 15,695, on Friday. The Nifty of the National Stock Exchange fell 46 points, or 1 percent, to 4,710.Asian market lower on Friday, as lingering concerns over Europe's debt crisis kept investors sidelined. So, Japan's Nikkei shed 0.1%; Hong Kong's Hang Seng lost 1.4%; Singapore's Strait Times index slid 1.2%; China's Shanghai Composite index slipped 0.7% and South Korea's Kospi fell 0.9%.European markets fell amid initial volatility as investors continued to fret over euro-zone troubles and Hungary suffered a downgrade. London's FTSE-100, France's CAC-40 and Germany's DAX slipped 0.3% and 0.6% in intra-day trade, on Friday.Meanwhile, Moody's Investors Service cut Hungary's government bond rating one notch to Ba1 late evening yesterday.The ratings firm retained a negative outlook on Hungarian bonds, saying it's looking increasingly uncertain the country will meet its fiscal consolidation and debt reduction targets.