Section 50(3)(b) in Tamil Nadu Pension Rules, 1978
(b)The amount of non-contributory family pension payable under sub-rule (3) shall be of one-half of the pension sanctioned to the Government servant at the time of his retirement and if the pensioner had, before his death, commuted a part of his pension, the commuted part of the pension shall be deducted from the amount of non-contributory family pension: