Aerial photo taken on March 13, 2021 shows a view at the Yuantouzhu scenic spot of the Taihu Lake in Wuxi, east China's Jiangsu Province. (Xinhua/Yang Lei)

The water quality of Taihu Lake, China's third-largest freshwater lake, improved last year and reached its best level since 2007, the local authority said Tuesday.

In 2023, the lake's phosphorus level stood at 0.052 mg/L and nitrogen was 1.09 mg/L, down by 17.5 percent and 9.9 percent respectively compared with the year before, said the government of Jiangsu Province where the lake is located.

The lake reported 53 algae outbreaks last year, a drastic decline from 104 recorded the year before, officials told a press conference.

Meanwhile, the lake's aquatic vegetation area reached 200 square kilometers, up 25.8 percent year on year.

Located in the lower reaches of the Yangtze River, Taihu Lake is an important water source for 17 million residents in one of China's densely populated and economically developed areas.

Taihu suffered a severe algae outbreak in 2007, prompting the provincial government to launch a pollution treatment program. Although not poisonous, the algae bloom decimates fish and pollutes the water.