KENDRAPADA: Lack of oxygen due to pollution is the main reason behind the death of a large number of fish in Bata river and other water bodies in the port town of Paradip recently, said Puskar Behera, the regional officer of Odisha State Pollution Control Board (OSPCB). “The scientists of OSPCB tested the water from Bata river and its nearby water bodies in our laboratory in Bhubaneswar and found that the fish died due to lack of oxygen. The oxygen level was only 2 milligram per litre as opposed to the required 7 milligram per litre in the river. They have also noted that the presence of biological oxygen demand had contributed to the death of fish on December 31 in the water bodies in the port town Paradip,” added the officer. “We found that the drop in the level of dissolved oxygen in the river has led to the death of hundreds of fish. The scientists came to know there was only 2 milligram of dissolved oxygen per litre in the water of Bata river,” added Behera.