What is the ruling on working in a department that handles correspondence with usurious banks and customs for importing spare parts for a company whose main dealings are permissible? And what is the ruling on studying university specializations that relate to dubious transactions, such as studying law, international trade, or import and export?

Dealing with usurious banks is strictly forbidden, except in cases of necessity when no Islamic alternative is available, provided the transaction is free from usury. The guarantees offered by usurious banks are of two types: permissible and impermissible. Assisting with impermissible guarantees is not allowed. Customs duties are also of two types: permissible and impermissible. It is permissible to use stratagems to waive impermissible duties or reduce them when compelled. As for studying law and international trade, their rulings have been previously clarified in earlier fatwas.