Staff members work at a warehouse of Ganglu Iron & Steel Co., Ltd. in Tangshan, north China's Hebei Province, May 1, 2024. International Workers' Day is observed annually on May 1. (Photo by Liu Mancang/Xinhua)

This aerial drone photo taken on May 1, 2024 shows a construction site of a river dam in Pingyi County, Linyi City, east China's Shandong Province. International Workers' Day is observed annually on May 1. (Photo by Wu Jiquan/Xinhua)

Staff members check the body of a bullet train at a train maintenance workshop in Nanning City, south China's Guangxi Zhuang Autonomous Region, May 1, 2024. International Workers' Day is observed annually on May 1. (Xinhua/Cao Yiming)

A staff member cleans the body of a bullet train at a train maintenance workshop in Nanning City, south China's Guangxi Zhuang Autonomous Region, May 1, 2024. International Workers' Day is observed annually on May 1. (Xinhua/Cao Yiming)