Thank you for writing to us. Before answering your query, I would like to thank you for your esteemed selfless service to the nation.
As I understand from the facts provided by you the claim you are referring is in the nature of reimbursement expenses . Which means you have spent your own money during your duty for official purposes and hence receiving it back from the employer as the same is due by them at the first place.
There is no earning or generation of income in this kind of claims as these are supposed to be paid by the employer in the first place for the carrying out your duty. It is merely for the administrative ease that, you are spending first and claiming the same amount from the employer.
Hence this will not be treated as income and is not subject to income tax. This is an expense paid out of your already earned income for which you are anyway going to pay tax. So, if you pay tax on the reimbursement claim it will like a double taxation, which is not allowed as per law.
For better understanding, please find an example below
Monthly Salary : 93,000
Less : Official expenses : (10,000)
Add: Reimbursement claim: 10,000
Final Income : 93,000
Hence your final income does not change with or without your claim as it is not an income earned by you , rather only a reimbursement of amount spent by you on behalf of your employer. So, the amount you receive as your claim is not taxable.