Must be a coincidence that the Chicago Riot Police helmet is light blue, just like the UN Peace Keepers helmets.
Chicago Police Department riot helmet is Light Blue. Specifically, the Seer S1711-CPD Ballistic Helmet with Face Shield, developed exclusively for Chicago Police Department specifications, features a CPD Light Blue painted Ballistic Shell with a smooth surface, high gloss clear coat, and the CPD Star affixed under high gloss clear coat.