Dear Sarita,
Let me clarify everything to you.
1. One gets a pension if one is a member of a pension fund. That means if your employer/organization has a pension scheme (self or outsourced). Many organizations do not have one, and only benefits are gratuity and PF.
2. The pension is regulated by the pension rules. Generally, the minimum service for a pension is 10 years. Further, if you do 33 years of service, you get full pension as per the formula, which will be based on your Pay. If you have 20 years plus service, then some organizations give the benefit of 5 years of notional service. Thus, if you have put in 20 years of service, your pension will be calculated by adding 5 years to your service.
3. Please note that whatever pension is fixed for you (generally basic for this purpose) on your retirement, one-third you can commute. This means if your basic is fixed at 9000/-, you can commute one-third, i.e., 3000/- per month for say 15 years (15 years does not mean you will get exact 15 years, but it is based on some factors depending on your age). Let us say your factor is 13; then your commutation amount will be 3000 x 12 (months) x 13 (factor in your case) = Rs. 468000/-
4. Generally, the 2nd commutation is allowed after 15 years.
5. Please remember your reduced basic every month after commutation will be 6000, and you will get DA on the original basic of 9000/-
Hope now you understand.
Pension is after retirement, commutation is pre-empting some part of your basic pension. These are social security measures.
Thanks.
Prabhaker Verma