Is Zakat obligatory on the money a person possesses, while also having a car installment debt, or is this money considered a debt?

The majority of scholars hold that debt prevents the obligation of zakat on internal wealth (gold, silver, currency, trade goods). So, if the debt consumes the nisab (minimum threshold) or reduces it below the nisab, there is no zakat. The preferred view, according to Ahmad and some scholars, is that debt does not prevent the obligation of zakat on external wealth. They cite what was narrated from Uthman ibn Affan, may Allah be pleased with him, as evidence. If the debt does not reduce the nisab, then it is deducted by its amount, and the remainder is subject to zakat. Whoever has other surplus wealth beyond their basic needs should use it to offset the debt in order to pay zakat on their zakatable wealth. If they do not have a surplus beyond their basic needs, the entire debt is deducted from the zakat-eligible wealth, and zakat is paid on the remainder if it does not fall below the nisab.