Is zakat obligatory on a plot of land that yields no income and is still being paid for in installments? If so, what is the value upon which zakat is due?

If the land was purchased for personal ownership, there is no zakat on it, based on the Prophet's (PBUH) saying: "We were commanded to extract charity from that which we prepare for sale." However, if it is for trade, zakat becomes obligatory on it by valuing it at the market price when a year has passed, and a quarter of a tenth (2.5%) is to be paid after deducting the remaining installments as debt, based on the saying of Uthman ibn Affan (may Allah be pleased with him): "Whoever has a debt, let him pay his debt until your wealth becomes available so you may pay zakat from it." If there is other surplus wealth beyond basic needs, it should be used to offset the debt, and the entire value of the land is then subject to zakat.