Zhou Hong, a sanitary service worker, shows her battery heated shoe pads at her home in Mudanjiang City, northeast China's Heilongjiang Province, Jan. 23, 2018. The lowest temperature fell below minus 30 degrees Celsius in Mudanjiang on Tuesday. Zhou Hong, a monitor of a sanitary service team, got up at 3 a.m. as usual to start her work. To keep warm, Zhou wore two extra coats and three hats for she would work outside for more than 10 hours.(Xinhua/Zhang Chunxiang)