HOHHOT — North China's Inner Mongolia autonomous region has diverted 3.65 billion cubic meters of water from the Yellow River to a lake in a sandy area for ecological water supplement over the past 15 years, authorities said.

The water supplement project was launched in 2007 for the Ulan Suhai Lake, the largest freshwater lake in the Yellow River basin, said Li Bin, deputy chief of the regional department of water resources.

Located on the northern bank of the Yellow River in the desert and semi-desert area in the city of Bayannur, the Ulan Suhai Lake is dubbed the "pearl beyond the Great Wall."

Every spring, locals dredge the water channel connecting the lake and the Yellow River, China's second-longest waterway, and then divert water to the lake to reduce the flooding pressure along the river and improve the environment of the dry, sandy area.

Now, the lake has seen its size stabilized at 293 square km with improved water quality, said Li.