Is it permissible to delay the Maghrib prayer until after the completion of university exams that begin half an hour before the Maghrib call to prayer and end two hours after it?

Delaying prayer beyond its prescribed time is a major sin. One must be diligent in performing prayers on time. However, if it is difficult to do so and would cause harm, there is no sin in combining the Maghrib and Isha prayers during the time of Isha due to a need.