The National Aquatic Resources Research and Development Agency (NARA) has launched an investigation into the deaths of ducks and other birds near the Beira Lake in Colombo.
Residents of the area say that the birds started dying after chemicals were added to the water to reduce the stench caused by stagnant water in the lake.
The agency said that further tests will determine whether chemicals in the water are responsible for the deaths of the birds.
However, initial findings by NARA have revealed that the water in the Beira Lake is reported to have low oxygen levels.