What is a requirement for takeoff or landing in a built-up area not designated for aircraft operations?

In built-up areas not specifically designated for aircraft operations, the primary concern is safety and preventing harm to people and property on the ground. Therefore, for a takeoff or landing in such areas to be permissible, it is crucial that the flight must not pose a hazard to persons or property on the surface. This requirement ensures that pilots conduct their operations with a high level of situational awareness regarding the potential risks involved when flying over densely populated regions, thereby prioritizing safety.

While the other options mention important considerations for flight operations, they don’t address the central requirement for safety in built-up areas as directly as this option. For instance, while having a designated location for operations can be beneficial, it is not a strict requirement for every situation. Similarly, authorization for police operations or approval from local government may apply in specific instances, but maintaining safety for those on the ground remains the foremost priority when considering flights in non-designated areas.