Is Zakat obligatory on the value of the car or on the monthly income derived from it?

Zakat is not obligatory on the value of the car itself. Rather, it becomes obligatory on its rental income if it reaches the nisab (minimum threshold) either on its own or by combining it with other assets, and a full year (hawl) has passed on it. The amount of zakat is 2.5%, and its nisab is equivalent to 85 grams of gold or 595 grams of silver.