Staff members work at a honey company in Longyao County, north China's Hebei Province, May 22, 2018. The annual sales revenue of honey and related products in Longyao are over 6.28 million U.S. dollars. (Xinhua/Mu Yu)

Staff members work at a honey company in Longyao County, north China's Hebei Province, May 22, 2018. The annual sales revenue of honey and related products in Longyao are over 6.28 million U.S. dollars. (Xinhua/Mu Yu)

A worker collects honey at a company in Longyao County, north China's Hebei Province, May 22, 2018. The annual sales revenue of honey and related products in Longyao are over 6.28 million U.S. dollars. (Xinhua/Mu Yu)

Workers paste trademark of honey products in Longyao County, north China's Hebei Province, May 22, 2018. The annual sales revenue of honey and related products in Longyao are over 6.28 million U.S. dollars. (Xinhua/Mu Yu)