The News Minute | February 06, 2015 | 09.20 am ISTIt’s finally confirmed that the reason for thousands of dead fish being washed ashore Chennai’s Urur Kuppam beach was due to sewage pollution in the Adyar estuary. The Biochemical Oxygen Demand found in a water sample tested showed five times the safe amount for aquatic life, reported The Hindu. Tested at the Tamil Nadu Water Supply and Drainage Board , the water sample having a reading above 6 mg/l was not suitable for fish to survive. Not only did it have sewage content, the water sample also was found containing chromium , zinc, copper and iron. According to K Saravanan , a fishermen activist , the trend exists along the coast where many establishments constantly discharge sewage into the estuary, said the report.