Cash purchase

cost of acquisition shall be reduced by the amount paid in cash. in your case full cash payment, hence cost of acquisition shall be 0

CASH TRANSACTION OF MORE THAN RS 10,000 IS NOT ALLOWED 

Violation of 40a(3)

Connect with 43b actual payment
Actual payment reduce by amount paid in cash

And connect with sec 32 depreciation
Depreciation should be calculate on actual cost

So depreciation will be NIL.

if the vehicle is purchased for your business purposes, then as per section 43, cash payment in excess of 10000 will be reduced from the cost of assets and no depreciation will be allowed. if it's for personal use, then there's no tax implications however the seller will have to face penal provisions under 271DA for violating the provisions of section 269st