Is Zakat obligatory on money used to purchase cars on installment, where the installments are paid first-and-foremost?

Zakat (definition) is obligatory on car installments if a year has passed since the principal amount was acquired. Zakat is due on what has been collected and on what is owed by solvent, non-procrastinating individuals, each time a year passes, provided that the amount reaches the nisab (definition) (minimum threshold) by itself or when combined with other assets. As for installments paid before the passing of a year, no zakat is due on them.