Hainan

Hainan does not have an official flag. However, their flag is used in the National Games of China. It features a red background with yellow lettering of the province's name.https://www.reddit.com/r/vexillology/comments/tdym49/flags_of_chinese_provinces_at_the_national_games/#lightbox
==References==
Category:China
Category:Red background
Category:Yellow
Category:Lettering
Category:Unofficial flags