Section 2(1)(c) in The Orissa Electricity Reform (Transfer of Assets, Liabilities, Proceedings and Personnel of Gridco to Distribution Companies) Rules, 1998
(c)"Area of Supply" means the area of distribution and supply of electricity in the specified zones and being in the case of Cesco, the Central Zone; in the case of Wesco, the Western Zone; in the case of Nesco, the North Eastern Zone and in the case of Southco, the Southern Zone;