Hi Nandini, I think you're from TN, if that's correct. As our seniors suggested, PT is a monthly payout as per TN state government rules. I didn't find any half-yearly and annual payments except for Managing Partners. So, the best thing to do is to deduct on a monthly basis as per state government policy as shown below:
Monthly salary and tax deductions
Monthly salary (in Rs.) Tax (in Rs. Per month)
Up to Rs.3,500 - Nil
Rs.3,501 to Rs.5,000 - Rs.22.5
Rs.5,001 to Rs.7,500 - Rs.52.5
Rs.7,501 to Rs.10,000 - Rs.115
Rs.10,001 to Rs.12,500 - Rs.171
Above Rs.12,500 - Rs.208
Please review and let me know if you need any further clarification.