Aerial photo taken on Jan. 6, 2021 shows water flowing in a section of the Halha River in the city of Arxan of Hinggan League, north China's Inner Mongolia Autonomous Region. Despite Arxan's frigid winter cold, this geothermally-affected section of the Halha River never freezes even when the temperature drops to as low as minus 40 degrees Celsius. (Photos: Xinhua)

Aerial photo taken on Jan. 6, 2021 shows water flowing in a section of the Halha River in the city of Arxan of Hinggan League, north China's Inner Mongolia Autonomous Region. Despite Arxan's frigid winter cold, this geothermally-affected section of the Halha River never freezes even when the temperature drops to as low as minus 40 degrees Celsius.

Photo taken on Jan. 6, 2021 shows water flowing in a section of the Halha River in the city of Arxan of Hinggan League, north China's Inner Mongolia Autonomous Region. Despite Arxan's frigid winter cold, this geothermally-affected section of the Halha River never freezes even when the temperature drops to as low as minus 40 degrees Celsius.

Aerial photo taken on Jan. 6, 2021 shows water flowing in a section of the Halha River in the city of Arxan of Hinggan League, north China's Inner Mongolia Autonomous Region. Despite Arxan's frigid winter cold, this geothermally-affected section of the Halha River never freezes even when the temperature drops to as low as minus 40 degrees Celsius.

Photo taken on Jan. 6, 2021 shows water flowing in a section of the Halha River in the city of Arxan of Hinggan League, north China's Inner Mongolia Autonomous Region. Despite Arxan's frigid winter cold, this geothermally-affected section of the Halha River never freezes even when the temperature drops to as low as minus 40 degrees Celsius.

Photo taken on Jan. 6, 2021 shows water flowing in a section of the Halha River in the city of Arxan of Hinggan League, north China's Inner Mongolia Autonomous Region. Despite Arxan's frigid winter cold, this geothermally-affected section of the Halha River never freezes even when the temperature drops to as low as minus 40 degrees Celsius.

Aerial photo taken on Jan. 6, 2021 shows water flowing in a section of the Halha River in the city of Arxan of Hinggan League, north China's Inner Mongolia Autonomous Region. Despite Arxan's frigid winter cold, this geothermally-affected section of the Halha River never freezes even when the temperature drops to as low as minus 40 degrees Celsius.

Photo taken on Jan. 6, 2021 shows water flowing in a section of the Halha River in the city of Arxan of Hinggan League, north China's Inner Mongolia Autonomous Region. Despite Arxan's frigid winter cold, this geothermally-affected section of the Halha River never freezes even when the temperature drops to as low as minus 40 degrees Celsius.