It depends on the definition of gross salary itself. If the gross salary includes only a fixed and pre-decided amount (the amount fixed at the time of the contract of employment), then that would qualify for deduction in case of absence from work (leave without pay), overtime payment, etc. For holidays, there is no additional payment, but when the salary is fixed per month, the holiday pay is included in it.
Regarding deduction and contribution for PF, the same gross salary may be considered subject to a maximum of Rs. 15,000.