income tax allowance

Now i m sharing something yesterday i was filling some return and according to law its a case of police department where i was filling itr i have checked all detail in deduct allowance like hra etc according to rule but i found one allowance which was prott. Allowance plz if any body know then plz tell me is there any special deduction allowe for police department
Bcz yesterday i met with one advocate who was also filling itr of police and he was reducing salary till full refund.
After seeing this i am very confuse that can it possible any one can reduce salary for itr form 16 doesn't matter