Combo photo shows a man lying in a "fire box" on Dec. 16, 2018 (L), and women doing knitting work around a "fire box" on Dec. 15, 2018 (R), in Huaihua City of central China's Hunan Province. As the temperature drops, people in Hunan use various heating devices to fight against the cold weather. (Xinhua/Yin Zhong)