eligibility of service element and broadbanding of disability pension

I am ex cpl from airforce and voluntarily retired after serving 11.5 years. I am having atrubable disability of 20% presently getting 20% disability pension amounting 1685 rupees. I would like to know am i eligible for 1. Broadbanding of disability pention ie. 50% . 2. am i eleigible for service element of disability pension. 3. am i eligible for echs facility.