Prop drilling - props are used to pass data from parent to CHILD. The use of props is effective until deep chaining of components is encountered.
Prop drilling is caused when a distant component in a LARGE component tree and a deeply nested component want something from a distant ancestor component. In this case, all of the intermediate components should have to pass props from the distant ancestor across the entire chain.
It involves the PASSING of props ALONG the entire chain for the distant component to use the data.
It is difficult to maintain, PRONE to bugs, and is hard to work.