BEIJING, July 21 -- China's water quality levels saw steady improvement in the first half of this year, data from the Ministry of Ecology and Environment shows.

The proportion of surface water at or above tier three in the country's five-tier water quality system rose 2.1 percentage points year on year to 87.8 percent during the period, according to the ministry.

The proportion of surface water at tier five, the lowest level, stood at 1 percent, down 0.1 percentage points from the same period of last year.

China's major rivers, lakes and reservoirs saw improved water quality in the first half. The proportion of water at or above tier three in the Yangtze River, the Yellow River and other major river basins rose 1.8 percentage points year on year to 89.1 percent.

Lakes and reservoirs with water at or above tier three accounted for 80.3 percent of the 208 key lakes and reservoirs monitored by the government in the first six months, up 4.1 percentage points from the same period of 2022, the data shows.