This is because the air pressure around the plane is low when it is flying at high altitude, so the boiling point of the liquid also decreases with the elevation. For example, the boiling point of water is 100℃ on the ground, 80℃ in mountainous areas and even lower in the stratosphere. If you carry liquid on the plane, the liquid will boil due to the decrease of air pressure, producing a lot of gas. There is not much room for these gases on the plane, which will also cause local high pressure and there will be a danger of explosion.

In addition, when the plane takes off and lands, it needs to open the shutter. First, it is convenient for rescuers outside the plane to observe the situation in the cabin and rescue them as soon as possible. The second is auxiliary lighting, which prevents accidents when the lighting facilities in the cabin cannot be used, and helps passengers observe the surrounding environment.

Extended data

Announcement on Prohibiting Passengers from Carrying Liquid Articles on Domestic Flights stipulates that:

First, passengers on domestic flights are forbidden to carry liquid articles with them, but they can send them, and their packaging should comply with the relevant provisions of civil aviation transportation.

Two, passengers carry a small amount of cosmetics for personal use, each cosmetic is limited to one, the container volume shall not exceed 100 ml, and should be placed in a separate bag, open the bottle for inspection.

3. If an overseas passenger needs to transfer to a domestic flight at a domestic airport, the duty-free liquid articles he brings into the country should be put in a transparent plastic bag with intact bags and sealed bags, and the shopping vouchers should be presented before they can be carried.

Yinchuan evening news-a little common sense that you must know when flying.