Depreciation on old car

Hi,

An assessee had purchased a car 2 years back on say 1/4/2013. He has started a business from FY 2015-16 and used the car for business. Earlier he was a salaried employee and used the car for personal purposes (so no question of depreciation for past 2 years).

Now, In Fy 2015-16, on what amount should I calculate depreciation?

On the WDV after allowing depreciation for past 2 years

or

on the cost?