Closure_of_Intersection_is_Subset_of_Intersection_of_Closures

Let $T$ be a topological space. Let $I$ be an indexing set. Let $\forall i \in I: H_i \subseteq T$. Then $\displaystyle \left({\bigcap_I H_i}\right)^- \subseteq \bigcap_I H_i^-$ where $H_i^-$ denotes the closure of $H_i$.