Around 8 a.m. Saturday, the optical phenomenon known as halos appear in the sky in the city of Genhe in the Inner Mongolia autonomous region, known as the nation’s “Pole of Cold.” Halos are a rare atmospheric phenomenon caused by the refraction and reflection of light from the sun or moon by ice crystals suspended in the atmosphere. Photo: Ding Gang/Caixin

A real-time temperature display shows -20 degrees Celsius (-4 F) in Genhe. The National Climate Center dubbed Genhe “China’s Pole of Cold” in December 2018. Photo: Ding Gang/Caixin

A person stands on a snow slope, gazing at the suspended ice crystals and fog on Saturday in Genhe. Photo: Ding Gang/Caixin

The dispersion of light causes the inner edge of a halo to appear reddish and the outer edge to take on a bluish hue. Photo: Ding Gang/Caixin

Fog and clouds appear in the skies over Genhe. The largest number of extreme cold days ever recorded in the city was 69, and the longest continuous run of such days was 27. Photo: Ding Gang/Caixin

Light columns from a halo stream down over Genhe. Photo: Ding Gang/Caixin

A halo over Genhe. Photo: Ding Gang/Caixin