Communities from Nigeria's oil-producing Niger Delta are suing the government and international oil companies to stop the flaring of natural gas, an environmental activist backing the action said on Monday...The legal claim is against the Nigerian government, the Nigerian National Petroleum Corporation and oil majors Shell, Exxon [ExxonMobil], Chevron, Total and Agip [part of ENI]..."We are following the developments and will make a response at the appropriate time," said a spokesman for the Nigerian arm of Shell.