Why can't girls wear blue hats?

There is no law that girls can't wear blue hats. According to the inquiry of China Travel Service. As of September 7, 2023, the state has not promulgated laws and regulations that girls can't wear blue hats, but girls can wear blue hats. China citizens have the freedom to wear clothes and hats. As long as there are no illegal slogans printed on clothes and hats, they can wear any style and color.