If your flight is delayed or cancelled due to an unforeseeable or extraordinary event, it is considered force majeure. In such cases, the airline is not held responsible and you are not entitled to compensation under EU regulations.
Examples of force majeure include:
strikes by airport or air traffic control staff
extreme weather conditions
political unrest or instability
natural disasters
security risks or medical emergencies
Even though compensation is not granted, the airline is still obligated to assist you, for example by offering food, accommodation, or rebooking options, depending on the situation.