Oil-polluted Nigerian communities can now sue Shell in English courts.
The UK Supreme Court gave the ruling Friday saying that the cases brought by the Bille community and the Ogale people of Ogoniland against Royal Dutch Shell were arguable.
The decision is seen as victory for the communities after a five-year battle and which has now overturned a Court of Appeal ruling.
Royal Dutch Shell has said it is dissapointed by the ruling and argues it does not dispute that pollution had been caused. It however says it could not be held legally responsible for its Nigerian subsidiary.
Shell is responsible for about 50% of the Niger delta's oil production.
The Niger Delta communities of more than 40,000 people say decades of pollution have severely affected their lives, health and local environment.
In 2011 the UN concluded it would take 30 years to clear up the vast amounts of pollution in the Niger Delta.