whether he lost earning capacity due to injury.

Normally government employees are not removed or prematurely retired on account of disability .

but if there is more than 50 % disability and employee is not removed by the government but employee himself resigns on account of inability to perform duty , then what is the remedy available to him? 

a rerely known and used provision

provision of The Persons with Disabilities (Equal Opportunities, Protection of Rights and Full Participation) Act, 1995

47. Non-discrimination in Government Employment - (1) No establishment shall dispense with, or reduce in rank, an employee who acquires a disability during his service:

Provided that, if an employee, after acquiring disability is not suitable for the post he was holding, could be shifted to some other post with the same pay scale and service benefits:

Provided further that if it is not possible to adjust the employee against any post, he may be kept on a supernumerary post until a suitable post is available or he attains the age of superannuation, whichever is earlier.

(2) No promotion shall be denied to a person merely on the ground of his disability:

Provided that the appropriate Government may, having regard to the type of work carried on in any establishment, by notification and subject to such conditions, if any, as may be specified in such notification, exempt any establishment from the provisions of this section.