Chinese authorities are considering introducing a new import standard for zinc concentrate to combat pollution. The proposed standard will introduce limits on the content of thallium, fluorine and chlorine in zinc concentrate while tightening existing limits on mercury and arsenic content. Some Chinese smelters already have limits on thallium content in zinc concentrate. Smelters without such controls will be more affected by the new standard. But tighter restrictions on fluorine, chlorine and mercury content will have a much harsher impact on imports. The amount of zinc concentrate available to China to import could be halved by the new standard. This means demand from Chinese smelters will not be met and the rest of the world will have a zinc concentrate surplus. This situation could lead to ROW contract TCs moving higher and China spot TCs lower.