Around 200 polluted lakes in Hanoi will be treated with a special substance imported from Germany, said Hanoi Sewerage and Drainage Limited Company.

Hanoi Sewerage and Drainage Limited Company sent the municipal authorities a report on surveying lakes in the city. According to the report, Hanoi's inner-city areas have 119 lakes, including 72 polluted lakes which need to be dealt with in the fourth quarter of this year.

Fish found dead in the West Lake

Meanwhile, the city's outlying districts have 1,510 lakes and ponds. Among those, 100 lakes have been proposed to be treated for serious pollution.

Hanoi authorities have tested a special product from Germany to clean water in some polluted lakes such as Giap Bat, Ho Me and Ba Mau with positive results. Local people have also provided positive feedback as the lakes no longer emit a bad odour.

Following the successful trial, the chemical will be used for cleaning the remaining polluted lakes of the city.

Over 10 tonnes of fish have died in the West Lake in Hanoi since October 1 due to lack of oxygen according to local authorities.

Experts warned that the capital may lose its green lungs as many lakes in Hanoi are disappearing because of construction or have been heavily polluted by households waste for years.

About 650,000 cubic metres of wastewater is discharged into the river system each day. However, the capital only has three waste treatment plants with total capacity of 206,000 cubic metres a day. The Institute for Water Supply, Sewerage and Environment warned that Hanoi's underground water sources are also being heavily polluted.