Kindly let me know the Legal and statutory position with regard to the following points

1. What is the minimum basic and da to be fixed for gross salary of Rs.7500/ - Rs. 6000/- Rs. 5000/- Rs.4500/- Rs.3500/-

2. Can the bonus and gratuity and leave allowances can be apportioned as part of the salary and showed in the pay slip ?

3. What are all the allowances that are exempted from Gross Salary for calculating ESI