Farmers pick tea leaves at a base in Zhangjiajie, central China's Hunan Province, Sept. 5, 2018. Tea fields here have entered autumn harvest season recently. (Xinhua/Wu Yongbing)

A farmer pick tea leaves at a base in Zhangjiajie, central China's Hunan Province, Sept. 5, 2018. Tea fields here have entered autumn harvest season recently. (Xinhua/Wu Yongbing)

A farmer pick tea leaves at a base in Zhangjiajie, central China's Hunan Province, Sept. 5, 2018. Tea fields here have entered autumn harvest season recently. (Xinhua/Wu Yongbing)

Farmers pick tea leaves at a base in Zhangjiajie, central China's Hunan Province, Sept. 5, 2018. Tea fields here have entered autumn harvest season recently. (Xinhua/Wu Yongbing)