In China, in order to express the mourning for the deceased relatives and respect for the living, some places have the custom of wearing black gauze. This custom is usually carried out within a period of time after the death of a loved one. People who wear black veil are usually immediate family members, such as spouses, children, parents, etc.

Wearing a black veil is a symbol to express the sadness and sadness of losing a loved one. Black is considered as a color representing mourning and sadness. During wearing black veil, people usually avoid taking part in some festive activities, such as weddings and entertainment.

During the period of wearing black veil, relatives may also follow some other funeral etiquette, such as forbidding food and not cutting nails and hair. These are all to show respect and condolences to the dead.

It should be noted that different regions and ethnic groups may have different funeral customs, and the specific details may be different. If you are interested in the specific customs of wearing black veil, you can provide more background information, and I can also provide you with more detailed answers.