Commuted pension

Dear Sirs

Am stuck on following issue.....

A person is in receipt of commuted pension equal to 1/3 of total pension to be received by him in future. The person has received Gratuity also in previous years. My question is, is the pension commuted is eligible for total exemption as it is only a third part of total pension as provision of income tax states or exemption is available for 1/3 part of pension received this year.