KIEV, Nov. 15 - Ukraine’s largest mining and steel group, Metinvest, shut down its sinter plant in Mariupol for a month, responding to massive protests about the poor environment in the region, the company reported Thursday.

Ihor Syryi, the general director of Metinvest, said the company will try to improve the plant to try to reduce harmful emissions, but if little progress is made the plant may be shut down for good.