Permanent Account Number (PAN) was introduced by the Indian Income Tax Department in order to facilitate easy retrieval of information and matching information relating to an assessee's investment, payment of taxes, raising of loans, assessment, tax demand, tax arrears etc.The Permanent Account Number (PAN) is unique, national, and permanent. It is unaffected by a change of address, even between states in India. As a universal identification key the PAN helps to monitor all financial transactions of high net worth individuals and thereby indirectly prevent tax evation. Pan Card is issued by the Indian Income Tax Department under the supervision of the Central Board for Direct Taxes (CBDT) and is almost equivalent to a national identification number. It also serves as an important ID proof. From 1 January 2005 it has been made mandatory to quote the Permanent Account Number (PAN) on challans for any payments due to Income Tax Department. It is also compulsory to quote PAN in all documents pertaining to most financial transactions.