XINING -- Qinghai Lake, China's largest inland saltwater lake, has seen its largest water area since 2004 as a result of increased rainfall and improved ecological conservation.

Located in Northwest China's Qinghai province, Qinghai Lake's water surface area was over 4,625 square km by the end of September, about 381 square km more than 17 years ago, according to the provincial meteorological research institute, citing satellite remote sensing data.

"Increased rainfall was the main reason for the lake's water area expansion," said Zhao Huifang, a staff member at the institute. Zhao added that enhanced ecological conservation also played an important role.

Qinghai Lake is a crucial body of water to maintain ecological security in the northeastern Qinghai-Tibet Plateau. It is also a natural barrier for controlling the eastward spread of desertification.

The lake had been shrinking since the 1950s due to multiple reasons, such as human activities. The combined effects of conservation and changes to the regional climate turned things around.

In 2008, Qinghai launched a 10-year plan on the ecological environment protection and comprehensive management of the Qinghai Lake basin with a total investment of 1.57 billion yuan (about $245 million).

The improving ecosystem of the lake has benefited a variety of plant and animal species. For example, the number of bird species in the lake had increased from 164 in 1996 to 225 in 2020.