Whether Pension is exempt from Income Tax would depend on various factors including the fact where you are employed.
Taxation on Commuted pension
1) Government Employees : Wholly exempt.
2) Non-Government Employees
a) Where the employee receives gratuity, amount not exceeding the commuted value to the extent of 1/3rd of the pension is exempt.
b) In other cases : the commuted value of ½ of pension is exempt.