Mumbai, Dec. 16 -- Oil & Natural Gas Corpn Ltd dropped for a fifth straight session today. The stock is quoting at Rs 232.39, down 1.26% on the day as on 13:19 IST on the NSE. The benchmark NIFTY is down around 0.55% on the day, quoting at 25883.8. The Sensex is at 84762.05, down 0.53%.Oil & Natural Gas Corpn Ltd has lost around 6.31% in last one month.Meanwhile, Nifty Energy index of which Oil & Natural Gas Corpn Ltd is a constituent, has eased around 4.72% in last one month and is currently quoting at 35028.15, down 0.88% on the day. The volume in the stock stood at 26.05 lakh shares today, compared to the daily average of 77.31 lakh shares in last one month. The benchmark December futures contract for the stock is quoting at Rs 233.03,...