Taxability on fuel allowance

My wife is given an option of opting for fuel allowance from the company. She just need to submit the documents of car for it. The amount is 12000 per month which will come under the head of Fuel Allowance and the same amount will be reduced from the Special Allowances head.

I want to know whether the tax liability change in this case or it will remain the same since FBT is abolished the onus of paying tax on perquisites in on the employees.

Thank You in advance