People have fun on the bare river bed of Yellow River in Lanzhou of northwest China's Gansu Province, Feb. 18, 2021. Due to reduced runoff from its upper reaches, the water level in the Lanzhou section of Yellow River kept dropping in recent days, and part of its pebble-covered river bed there has become dry and bared. (Xinhua/Fan Peishen)

People have fun on the bare river bed of Yellow River in Lanzhou of northwest China's Gansu Province, Feb. 18, 2021. Due to reduced runoff from its upper reaches, the water level in the Lanzhou section of Yellow River kept dropping in recent days, and part of its pebble-covered river bed there has become dry and bared. (Xinhua/Fan Peishen)

People have fun on the bare river bed of Yellow River in Lanzhou of northwest China's Gansu Province, Feb. 18, 2021. Due to reduced runoff from its upper reaches, the water level in the Lanzhou section of Yellow River kept dropping in recent days, and part of its pebble-covered river bed there has become dry and bared. (Xinhua/Fan Peishen)

People have fun on the bare river bed of Yellow River in Lanzhou of northwest China's Gansu Province, Feb. 18, 2021. Due to reduced runoff from its upper reaches, the water level in the Lanzhou section of Yellow River kept dropping in recent days, and part of its pebble-covered river bed there has become dry and bared. (Xinhua/Fan Peishen)

People have fun on the bare river bed of Yellow River in Lanzhou of northwest China's Gansu Province, Feb. 18, 2021. Due to reduced runoff from its upper reaches, the water level in the Lanzhou section of Yellow River kept dropping in recent days, and part of its pebble-covered river bed there has become dry and bared. (Xinhua/Fan Peishen)