According to the report, Hanoi now has 112 lakes, covering total area of 6,959,305 square metres, marking a 72,540 square metres decrease in area compared to 2010.

Most of the lakes are still being used for various purposes including raising fish, growing vegetables and drainage with different management departments, which has led to them rapidly deteriorating due to poor cross-department links, the report said.

Many lake sides are also being used for parking, storing construction materials or even dumping waste.

Ba Dinh, Hoan Kiem, Dong Da, Hai Ba Trung, Cau Giay and Tay Ho districts have the largest number of polluted lakes. Some of the most polluted lakes are Linh Quang, Kim Lien, Ba Mau, Thien Quang and Giang Vo.

 Linh Quang Lake is seriously polluted

The report, however, showed that there are improvements in the environment and water quality of Hanoi’s lakes. More have been rated as being 'clean', while the number of lakes rated as 'very dirty' have decreased.

The report also suggested 10 recommendations for better managing lakes in Hanoi, including defining a clear function for each lake, assigning appropriate management bodies and considering an end to fish raising.

“Lakes, ponds and small rivers are valuable assets for the capital," director of CECR, Nguyen Ngoc Ly, said. "We need more proper measures and better co-operation between different individuals as well as agencies in protecting these assets."