Dear Gaurav,
Pensionable age with associated conditions has been prescribed under the Employee Pension Scheme, whereas the age for retirement on superannuation is fixed under the contract of employment or service regulations. The Payment of Gratuity Act, 1972, under which industrial employees stand to get gratuity, does not prescribe any age limit on retirement.
Therefore, when an employee is permitted by their employer to continue in service beyond the age of superannuation by means of extension or under a fresh contract of employment, for the purpose of gratuity, the entire service has to be taken notwithstanding the fact of being no member of the EPS.
If the employee is permitted to retire on attaining the age of superannuation, their gratuity should be paid forthwith. If their service is continued by means of extension, the extended period should also be counted for gratuity, taking the entire service as a single continuous spell of employment in the same establishment.