Mumbai, Sept. 5 -- Natural Gas futures are witnessing robust gains today, adding to recent upward momentum on steady demand as a break above $3 per mmbtu mark extends for the commodity. The U.S. Energy Information Administration (EIA) reported yesterday that working natural gas in storage across the United States increased by 55 billion cubic feet in the week ending August 29 compared to the previous seven-day period to reach 3,272 billion cubic feet. On an annual level, the figure marked a drop of 73 billion cubic feet. However, stockpiles grew by 173 billion cubic feet above the five-year average of 3,099 billion cubic feet. The total working gas remained within the five-year historical range. Firm cues from US equities and demand push fr...