A technician works at a laboratory of an environmental protection tech company in southwest China's Sichuan Province, Feb. 21, 2023. About 400 tons of waste oil is made each day by local catering service industry in Chengdu, among which 70 to 80 percent would be transported to environmental protection tech companies in Sichuan and recycled into products. (Xinhua/Liu Kun)

This photo taken on Feb. 21, 2023 shows oil storage tanks at an environmental protection tech company in southwest China's Sichuan Province. About 400 tons of waste oil is made each day by local catering service industry in Chengdu, among which 70 to 80 percent would be transported to environmental protection tech companies in Sichuan and recycled into products. (Xinhua/Liu Kun)

A worker operates equipment on the production line of an environmental protection tech company in southwest China's Sichuan Province, Feb. 21, 2023. About 400 tons of waste oil is made each day by local catering service industry in Chengdu, among which 70 to 80 percent would be transported to environmental protection tech companies in Sichuan and recycled into products. (Xinhua/Liu Kun)