A more thorough explanation:

Dillon's rule is a legal principle that states that a local government can only exercise the powers that the state has explicitly granted to it. This means that the local government cannot act beyond the scope of its authority.

For example, if a state grants a city the power to regulate traffic, the city cannot pass laws that regulate air pollution because it is not within its granted powers. However, if the state grants the power to regulate traffic, the city can also pass laws that are necessary and fairly implied from that grant, such as setting speed limits or regulating parking.

Dillon's rule is important because it helps to maintain a clear division of power between the state and local governments. It ensures that local governments do not overstep their authority and that the state retains ultimate control over important matters.