Visitors view an air conditioning system at an international rail transit expo in Changsha, central China's Hunan Province, Nov. 28, 2016. The expo and a high-speed rail economic forum kicked off here on Monday. (Xinhua/Wang Jingqiang)
Visitors view an air conditioning system at an international rail transit expo in Changsha, central China's Hunan Province, Nov. 28, 2016. The expo and a high-speed rail economic forum kicked off here on Monday. (Xinhua/Wang Jingqiang)