Volunteers take an oath during a launch ceremony for the volunteer program for the upcoming Shanghai Cooperation Organization (SCO) summit in Qingdao, east China's Shandong Province, May 24, 2018. (Xinhua/Li Ziheng)

Volunteers attend a launch ceremony for the volunteer program for the upcoming Shanghai Cooperation Organization (SCO) summit in Qingdao, east China's Shandong Province, May 24, 2018. (Xinhua/Li Ziheng)

Volunteers take an oath during a launch ceremony for the volunteer program for the upcoming Shanghai Cooperation Organization (SCO) summit in Qingdao, east China's Shandong Province, May 24, 2018. (Xinhua/Li Ziheng)

Volunteers take an oath during a launch ceremony for the volunteer program for the upcoming Shanghai Cooperation Organization (SCO) summit in Qingdao, east China's Shandong Province, May 24, 2018. (Xinhua/Li Ziheng)