A UN report says it will cost up to $1bn and take 30 years to clean up the damage done by decades of drilling by Shell.<br /><br />Oil exploration in Nigeria's south for several decades has had a debilitating effect on the environment of the region.<br /><br />Shell, the Anglo-Dutch oil company, has been accused of serious failures in its handling of the pollution in the Niger Delta and shirking its responsibility.<br /><br />Activists have demanded that Shell's licence be revoked for the environmental disaster.<br /><br />But with 90 per cent of the government's revenue coming from petroleum exports, oil companies seem to have clear political leverage over the issue.<br /><br />Al Jazeera's Yvonne Ndege reports from southern Nigeria.
