BEIJING - Beijing saw visible progress in improving water quality in 2019, an official report showed Monday.

In 2019, the annual average concentration of potassium permanganate in Beijing's surface water stood at 4.62 mg/L, and the annual average concentration of ammonia nitrogen was 0.57 mg/L, down 5.9 percent and 41.8 percent from a year ago, respectively, according to a communique released by the Beijing Municipal Ecology and Environment Bureau Monday.

In 2019, Beijing monitored 96 sections of rivers in the five major water systems, with a combined length of 2,364.2 km. The share of rivers with water quality rated third grade and above increased to 55.1 percent, while the length of rivers with inferior water quality decreased by 11.5 percentage points over the previous year.

Meanwhile, Beijing monitored 22 lakes with a water surface area of 7.2 million square meters and the proportion of lakes with a national quality rating at Grade III or above was 61.2 percent, according to the communique.

A total of 18 reservoirs with an average water storage capacity of 3.39 billion cubic meters were monitored in Beijing in 2019, with 85.2 percent having good water quality.