A white card (Chinese: 白牌) is a citizen-owned automobile in Hong Kong used as an illegal unlicensed taxi.
The term is a reference to fake taxi licenses.
Before 1983, taxis in Hong Kong had black license plates, while private cars had white license plates.
[1] In the 1950s, Hong Kong taxis were limited in numbers.
People started their own illegal businesses, and operated without any licenses or government regulation.