Thousands of fish have been found dead in a famous lake in Hanoi over the past week, but concerned agencies have been slow to respond.
Most of the dead fish are small chubs, according to people living around the Truc Bach Lake in Ba Dinh District.
Dong Thanh Ha, an official of the Research Institute for Aquaculture No.1 said that a test done at noon on Monday showed there was nothing wrong with the lake's water in terms of oxygen concentration.
The water's pH factor at noon was slightly lower than the standard 7.0, indicating it contained acid, he said.
However, further tests and inspections were needed to identify the cause, he added.
In the meantime, related agencies were yet to collect the dead fish which have started smelling, driving away tourists and customers from surrounding restaurants, local people have complained.
They have pointed out that the dead fish are likely to flow to the adjacent West Lake through a drainage pipe, polluting the other lake as well.