Travelling with an oddly shaped bag? There are new rules you need to know if your flight takes you through Dubai International Airport.

Effective March 8, 2017, all bags lacking a flat surface will be rejected at check-in for flights to or through Dubai. The only option for passengers with oversized or irregularly shaped bags will be to pay to have their luggage repackaged in a box.

Dubai Airports said the strict new checked-luggage rules are intended to help improve service, reduce the risk of mishandled bags, and enhance the performance of the airport’s check-in and baggage operation. “Bags that are round or do not have a flat surface of any kind are by far the largest source of baggage jams,” said Ali Angizeh, vice president of terminal operations at Dubai International. “These jams can shut down sections of our system, delay baggage delivery to the aircraft, and inconvenience our customers.”

Airlines operating in Dubai have been notified of the baggage rule changes and encouraged to alert passengers; new warning signs have also been posted in the airport, and the information is being shared with travellers on the Dubai Airports website and mobile app. “We are trying to get the message out there as much as possible,” said Angizeh.

Dubai International Airport is one of the busiest air-travel gateways in the world, with a record 8 million passengers in January. That same month, the airport’s baggage system handled approximately 9.3 million pieces of luggage.