Sensex, Nifty slide 1% on Dec F&O expiry: Markets ended lower for the second straight session weighed down by Oil & Gas shares on continued fall in crude oil prices over recent months. Weakness in the China markets dampened the sentiments of the investors. Markets extend losses in the last trading hour of trading ahead of the expiry of December derivative contracts. The Nifty was down 92.90 points or 1 percent at 8174.10. The Sensex sunk 297.85 points or 1 percent at 27208.60. Shares of companies engaged in insurance business have moved higher by up to 4% after the Union Cabinet clears the Insurance Laws Amendment Bill.Asian stocks gained and the dollar stood tall on Wednesday thanks to surprisingly robust U.S. economic growth, helping investors head into the Christmas holidays in a more relaxed mood after the global market turbulence of the past two weeks. Japan’s Nikkei gained over 1% while Hang Seng is trading flat with a positive bias.