Is the system of purchasing apartments through banks considered unlawful due to usurious interest, and is Zakat obligatory on this apartment, considering it indirect wealth?

Purchasing an apartment with a bank loan that involves interest is unlawful (haram) according to Islamic law; it is usury (riba).

Whoever has engaged in such a transaction must repent to Allah, terminate the usurious contract, and return the principal to the bank, even if this necessitates selling the apartment.

As for the Zakat on the apartment: - If it is prepared for rent: There is no Zakat on the apartment itself. Rather, Zakat is due on its rental income if it reaches the threshold (nisab) and a full lunar year (hawl) has passed over it. The amount of Zakat is a quarter of a tenth (2.5%). - If it is prepared for sale: It is treated like trade goods, and it must be valued annually, and its Zakat must be paid.