Fishing boats and commercial vessels is the cause because some ships choose to pour gasoline into the river instead of money to get rid of, just because an oil tanker coming too.
Fishing boats and commercial vessels as the cause because some boats chose to pour oil into the river, instead of wasting money just to get rid of because the tanker, too.
Fishing boats and commercial vessels cause because choose to pour the oil into the river instead of money to get rid of because of oil tankers over too.