Greetings of the day!!!
As per GST norms perquisites which are under CTC will not attract any tax as its coming under Employee - Employer relation but perquisites above CTC will attract GST.
As you have mentioned the perks like petrol allowance, driver allowance, telephone/ internet allowance/ attire allowance etc all are already fully taxable than already you are following wrong taxable structure.
Please Contact good tax consultant and change the structure immediately.Below link will help to identify the tax saver component. Individual