VOICED : Anger in Nigeria's south over oil spill clean up delay

Ogoniland in southern Nigeria has been severely impacted by 50 years of oil exploitation, leading to environmental degradation and water pollution. The Nigerian government, with UN support, initiated a $1 billion cleanup project, but progress has been slow. Local environmentalists have taken action by planting trees to mitigate pollution. The region, rich in hydrocarbons, has attracted multinational oil companies, leaving behind a legacy of environmental damage and community frustration.

How did local environmentalist Michael attempt to counter the pollution?

What legacy has the oil industry left in Ogoniland according to the text?