An emergency rescue team member rappels down a cliff to collect litters during an emergency drill at Huangshizhai Village of Wulingyuan, Zhangjiajie, central China's Hunan Province, Nov. 10, 2021. (Xinhua/Zhao Zhongzhi)

Members of this non-profit organization regularly collect litters from precipitous cliffs in and around Wulingyuan, a scenic site on the World Natural Heritage List of UNESCO.

Photo taken on Nov. 10, 2021 shows an emergency rescue team member rappelling down a cliff to collect litters during an emergency drill at Huangshizhai Village of Wulingyuan, Zhangjiajie, central China's Hunan Province. (Xinhua/Zhao Zhongzhi)

An emergency rescue team member rappels down a cliff to collect litters during an emergency drill at Huangshizhai Village of Wulingyuan, Zhangjiajie, central China's Hunan Province, Nov. 10, 2021. (Xinhua/Zhao Zhongzhi)

Photo taken on Nov. 10, 2021 shows an emergency rescue team member rappelling down a cliff to collect litters during an emergency drill at Huangshizhai Village of Wulingyuan, Zhangjiajie, central China's Hunan Province. (Xinhua/Zhao Zhongzhi)

Aerial photo taken on Nov. 10, 2021 shows members of an emergency rescue team rappelling down a cliff to collect litters during an emergency drill at Huangshizhai Village of Wulingyuan, Zhangjiajie, central China's Hunan Province. (Xinhua/Zhao Zhongzhi)

Members of an emergency rescue team pack litters collected during an emergency drill at Huangshizhai Village of Wulingyuan, Zhangjiajie, central China's Hunan Province, Nov. 10, 2021. (Xinhua/Zhao Zhongzhi)

Aerial photo taken on Nov. 10, 2021 shows members of an emergency rescue team rappelling down a cliff to collect litters during an emergency drill at Huangshizhai Village of Wulingyuan, Zhangjiajie, central China's Hunan Province. (Xinhua/Zhao Zhongzhi)

Aerial photo taken on Nov. 10, 2021 shows members of an emergency rescue team rappelling down a cliff to collect litters during an emergency drill at Huangshizhai Village of Wulingyuan, Zhangjiajie, central China's Hunan Province. (Xinhua/Zhao Zhongzhi)

An emergency rescue team member rappels down a cliff to collect litters during an emergency drill at Huangshizhai Village of Wulingyuan, Zhangjiajie, central China's Hunan Province, Nov. 10, 2021. (Xinhua/Zhao Zhongzhi