Is it permissible to purchase a car in installments with a condition for an increase in case of late payment, knowing that the original interest rate is 0% and there is someone who will pay in case of inability to do so?

It is not permissible to enter into a contract that includes an obligation to pay interest on a debt due to late payment, as this is a usurious and forbidden condition. The resolution of the Islamic Fiqh Academy states that it is not permissible to oblige a debtor who is late in payment to pay an increase on the debt, because that is forbidden usury. Likewise, it is not permissible to issue an uncovered credit card or to deal with it if it stipulates an increase in usurious interest, even if there is an intention to pay within the grace period. And buying a new car is not a necessity that permits committing this prohibited act.