Outgoing Tamil Nadu Chief Minister O Panneerselvam visited Ennore, outside Chennai, nearly a week after two ships collided at port's anchorage and spilled around 20 tonnes of oil along the coastline. Taking stock of the situation, Mr Panneerselvam said that authorities have cleaned up 90 per cent of sludge in the affected regions of Tiruvallore, Chennai and Kancheepuram.