Tds on interest on deposits of government departments

There is no specific exemption from TDS, unless the department procure an exemption letter from their juridictional Income Tax Commissioner, stating the grounds for exemption from TDS 

such Govt bodies have specific norms for deposit, they can not deposit everywhere, and to avoid such hassle they seek prior approval of commissioner, for non deduction of TDS

such as universites, they have PAN in name of trust, and they dont like to make "fixed deposits with banks"unless its required obligatory for any specific purpose of carriculam.