Centralization is said process where concentration of decision making is in a few hands.
Centralization: the degree to which decision making is concentrated at single point in the organization is called a centralization process, in this process no lower employee is involved in decision making.
Decentralization is a systematic delegation of authority at all level of management and in all of the organization. In decentralized companies, authority is retained by the top management for taking major decision & framing policies concerning the entire process of the company’s work. Rest of the authority may be delegated to the middle & lower level of management.