"The court upheld all the points made by the community," said Nnimmo Bassey, director of Environmental Rights Action, a Nigerian campaign group that supported the legal case brought by the community in the delta city of Benin.

Gas is flared in the Niger Delta because of a lack of facilities to exploit the resource commercially. Giant orange flares burn around the clock in the vast region of mangrove swamps and creeks, many close to villagers' homes.

"It's a thing that goes on 24 hours a day, every day of every year. It causes explosions, constant noise and great heat. Many people have never had a time of quietness or a dark night because of these flares," Bassey told Reuters by telephone.

The ruling was against the government, state oil company Nigerian National Petroleum Corp. (NNPC) and Shell Development Petroleum Corporation (SPDC), the Nigerian arm of Royal Dutch Shell.

"Following the ruling, SPDC has immediately filed a notice of appeal challenging the validity of the judgment on the basis of violation of legal process," the company said.

"However, we wish to restate SPDC's commitment to ending routine flaring of gas in its Nigerian operations. It is a big undertaking for which the company has over the last five years, made significant investment of some $2 billion," it added.

Environmental group Friends of the Earth says more gas is flared in Nigeria than anywhere else in the world and Nigerian flaring causes more greenhouse gasses than all other sources in sub-Saharan Africa combined.

Activists say flaring poses a health risk for people who live nearby, and respiratory diseases such as asthma are rife in Niger Delta communities affected by flaring.

They also say pollution from flaring damages livelihoods by reducing crop yields.

The government has set a 2008 target to extinguish flares, encouraging companies to use the gas for export as well as power generation within Nigeria. Companies say projects are under development that will eventually enable them to stop flaring.

"By the end of 2004, five projects had been completed and commissioned and were collecting 33 percent of the associated gas that was previously flared, thereby eliminating routine flaring at 22 of our 73 flow stations," SPDC said.

But it has also said it would miss the 2008 target because of funding problems and would stop continuous flaring in 2009.