にあたり・にあたって

This grammar is used for formal or official situations to indicate a notable moment when something happens or a plan or action is undertaken. It emphasizes consequences, responsibilities, or actions tied to that particular moment. Commonly found in announcements, speeches, letters, and official documents. The form with にあたり is more formal/ceremonial, while にあたって is slightly more general but still polite; both are often used with verbs in dictionary form (e.g., start, undertake, prepare) or with nouns to mark the occasion. Note that it marks a turning point or a context in which something is decided or announced rather than describing a routine event.