In a unitary system of government, local offices are subject to a central authority.
A unitary system is a system of political organization in which most or all of the governing power resides in a centralized government. The opposite of a unitary system is a federal system.
In a unitary system all the decisions are made by the central government, the government delegates the authority and channels political decisions to sub- national units and local offices. But they only exercise the powers that the central government chooses to delegate to them.
A large majority of the world's states have a unitary form of government.