People enjoy the cool in an air-raid shelter in Nanjing, capital of east China's Jiangsu Province, July 15, 2018. The local government opened seven air-raid shelters for people to avoid summer heat, and provided free tea, free wifi, newspapers and medical service in some shelters. (Xinhua/Liu Jianhua)

People enjoy the cool in an air-raid shelter in Nanjing, capital of east China's Jiangsu Province, July 15, 2018. The local government opened seven air-raid shelters for people to avoid summer heat, and provided free tea, free wifi, newspapers and medical service in some shelters. (Xinhua/Liu Jianhua)

Photo taken on July 15, 2018 shows an air-raid shelter open to people in Nanjing, capital of east China's Jiangsu Province. The local government opened seven air-raid shelters for people to avoid summer heat, and provided free tea, free wifi, newspapers and medical service in some shelters. (Xinhua/Liu Jianhua)

People enjoy the cool in an air-raid shelter in Nanjing, capital of east China's Jiangsu Province, July 15, 2018. The local government opened seven air-raid shelters for people to avoid summer heat, and provided free tea, free wifi, newspapers and medical service in some shelters. (Xinhua/Liu Jianhua)