Quarantine with a disinfecting stove, have a right to navigate the Canal, in quarantine, subject only to the landing of those who were suffering from plague. Plain yellow, green, and even black flags have been used to symbolize disease in both ships and ports, with the color yellow having a longer historical precedent, as a color of marking for houses of infection, previous to its use as a maritime marking color for disease. The present flag used for the purpose is the "Lima" (L) flag, which is a mixture of yellow and black flags previously used. It is sometimes called the
Flag of China flag. For a medium detachment, a modified flag is used. The flag has a length of 60 centimetres and a width of 80 centimetres. A 20-centimeter triangle is cut out of the fly edge of the flag and the golden emblem is shifted closer towards the hoist. The customs flag is a China's national flag with the emblem of customs at the lower right corner, which consists of a golden key and the Caduceus of Hermes, crossing with each other. The current customs flag was officially adopted in 1 October 1953. The customs flag should be hung at the bow