Hi
in your strucute, add the conveyance and tranport which should be based on voucher system, this is partly tax free. also the telephone exp could be till 1200 and will be completely tax free.
Variable salary must not be part of the CTC and should be informed which will be dependant on the performance. this will help the employees to save a taxes as they are variable and not fix.
If you still want some more tax free income structure, add Daily Food allowance Rs50 in strucute and against which issue the food coupns. this will be tax free, and only 12% FBT will be liable to be paid on it. You can even add car allowance for the higher cadre persons which again will help them to reduce the tax on income.
Regards