The independence referendum in Catalonia was aimed at allowing residents to decide whether to pursue independence from Spain. Catalonia, a region with a distinct language and culture, has a long history of seeking greater autonomy, and tensions escalated leading up to the referendum date. The Catalan government, led by President Carles Puigdemont, initiated the vote in defiance of a ruling by the Constitutional Court of Spain, which had declared the referendum unconstitutional. On the day of the vote, police were deployed to prevent polling, resulting in clashes and allegations of police brutality against peaceful voters. Estimated turnout was calculated at around 43%, with over 90% of those who voted choosing independence. However, the low turnout and legal challenges highlighted the contentious and divided nature of the vote's legitimacy.

The event was characterized by both fervent support among independence advocates and strong opposition from the Spanish government, which undertook measures to disrupt the voting process. International reactions were mixed, with some countries supporting Spain's territorial integrity and others acknowledging Catalonia's aspirations for self-determination. The aftermath of the referendum fueled further political tensions in Spain, leading to a constitutional crisis and the eventual application of direct rule from Madrid. Despite its illegal designation, the referendum served as a crucial point in the ongoing debate over autonomy for Catalonia and raised questions about regional governance within Spain.