Is it permissible to pay a late fee imposed by the Engineers' Syndicate to obtain a license to practice the profession, knowing that it might be considered usury, or must one seek work in another field?

If the payment of union dues is delayed, it is considered a debt. The general rule is that any increase on a debt is forbidden, as it constitutes usury (riba). However, there are two exceptions to this: 1. If the creditor is compelled to resort to legal action to collect their debt, they are permitted to recover the litigation costs and attorney's fees incurred. 2. If the currency's value decreases by one-third or more, the creditor may demand compensation for this depreciation.

However, if the renewal of union membership is contingent upon paying interest on overdue amounts, and working in the field is impossible without paying it according to state law, then it is permissible. This is because the sin falls upon the one who mandated the payment, and it is treated like compulsory insurance imposed by states, which has been permitted due to need and necessity.