The Uttar Pradesh Pollution Control Board (UPPCB) on Monday sent a team to collect river water from Gomti barrage to find out its dissolved oxygen level. The step was taken after largescale death of fish was reported recently in the water stretch. UPPCB CEO DC Gupta said the dissolved oxygen level of the river at the point would be monitored along with the time for which the barrage gates were opened. "The gates were closed because the water level went down at Pipri ghat. When the dissolved oxygen level drops suddenly, fish do die," he said. The present dissolved oxygen level of the Gomti water at the barrage is 2 mg per litre against the ideal level of 4 mg/litre. "The rate at which oxygen dissolves in water decreases in summer and this creates problems. Fish can survive even in dissolved oxygen levels of 2 mg/litre only if it remains stable," Gupta said.