Is zakat obligatory on a residential apartment that is still under construction, with monthly installments being paid to the developer? And does the ruling on zakat differ depending on the intention: if it is for rent, then zakat is on the rent, and if it is for sale, then zakat is on its value each year?

If the apartment is intended for trade, then zakat is due on the apartment at its current value upon the completion of a full Hijri year from the time of its ownership. One-quarter of one-tenth (2.5%) of its value is to be paid when it is sold, regardless of its purchase price. As for installments, there is a difference of opinion among scholars regarding deducting debt from zakat-eligible wealth. If the funds are not available to pay zakat, there is no harm in delaying it until liquidity is available.