For encashment of leave, there are certain rules, and it's not just a policy matter of a company. The lawmakers who prescribed the leave for the employees also prescribed the rules of encashment. For example, in Section 79 and 80 of the Factories Act, it is stated that when an employee is on leave, he is entitled to the salary as if he were at work. Similarly, when any employee has left his employment, he is entitled to the wages of the balance of accumulated leave. In short, what a person would have received while at work, the same is receivable while on leave or for encashment of leave.
Any policy against legal provision cannot be a policy at all, for the simple reason it is going to invite trouble.
I agree with Kishor Kulkarni. If the company has its own service conditions, the conditions should not deviate or dilute the conditions of the existing Central Act. Thus, the employee is eligible for the leave salary equivalent to the salary he would have drawn if he were on duty. The allowances disallowed are compensatory allowances like conveyance, uniform cleaning, and food allowance.