What does the color identification of Taian filing system mean?

Easy to control. In order to facilitate the rapid identification and accurate control of airport, station, traffic entrance, residential area, isolation hotel, health station and other staff, Taian filing system color identification was installed. Taian is a prefecture-level city under the jurisdiction of Shandong Province. It is located in the middle of Shandong Province, bordering Jinan, the provincial capital, in the north, Qufu in the south, Linyi in the east and the Yellow River in the west.