Desk research against primary sources, with the issuing authority linked where a page states an official fee, rule or deadline.
The age threshold moves the requirement, not just the price — international chains generally hold the line at 25 with a credit card, while local companies willing to rent from 21 do so by adding a larger security deposit rather than by relaxing the standard, so the younger renter is trading a lower age bar for a larger amount held against the car.
A licence that is not in English or Arabic adds a second requirement on top of age, since an international driving permit is what lets a rental company actually read it — turning up with a valid licence in another script but no permit can stall the booking even if you clear the age and deposit requirements cleanly. The 1-year minimum validity is checked against your licence’s own expiry, so a licence that is technically valid but due to expire soon can also be refused.