What does the 24-hour green code background mean?

Nucleic acid detection takes 24 hours.

When the epidemic situation is serious, the requirements become higher. If you want to travel, you must learn the green code and have a 24-hour nucleic acid test. Wear a mask and protect yourself. It is best to carry alcohol with you for disinfection.

Because the epidemic is serious, for everyone's health, if you travel, you must make all preparations. The green code of the mask is a must.