This is a cryptic definition with a double reading. The surface reading asks why a cricket match might be delayed — and the answer is Extra reason cricket was held up? because if there's NO BALL to play with, the game would indeed be held up. But in cricket terminology, a "no ball" is a specific type of delivery that counts as an "extra" — a run scored that isn't credited to the batter. The whole clue works as a playful definition from both angles.