GUANGZHOU, China — Workers at the vast Guangzhou Steel mill here poured molten metal for the Great Leap Forward in the late 1950s, fought street battles during the Cultural Revolution a decade later and made many of the steel reinforcing bars used to build China’s export factories over the next 30 years. But as part of a national energy-efficiency mandate, the historic mill is to be closed, starting in stages later this year.

Government agencies in Guangdong Province, where Guangzhou is the capital, portray it as a tough but necessary measure intended to not only improve energy efficiency but also to reduce toxic air pollution from the mill.

“Our province is forthrightly in step with the national aim to get rid of outdated production capacity,” said a recent statement to announce the shuttering of the mill.