UEFA stadium categories
UEFA stadium categories are categories for football stadiums laid out in UEFA's Stadium Infrastructure Regulations. Using these regulations, stadiums are rated as category one, two, three, or four (renamed from elite) in ascending ranking order. These categories replaced the previous method of ranking stadiums on one to five star scale in 2006. A stadium must be rated as category four in order to host games in the playoffs of the qualifying stage for the UEFA Champions League, or any game in the main competition. Category four is also required to host any game in the main  competition of the UEFA Europa League, UEFA Europa Conference League, UEFA Nations League or the UEFA European Championship final tournament. UEFA does not publish lists of stadiums fulfilling the criteria for any of the categories defined in the UEFA Stadium Infrastructure Regulations. General. If a retractable roof is present, its use will be directed by consultation between the UEFA delegate and the main assigned referee. Although the minimum stadium capacity for category four is 8,000, it is required to host the UEFA Europa Conference League final, and only one stadium with a capacity less than 60,000 has been selected to  host a UEFA Champions League (Estádio do Dragão for the 2021 final) and the UEFA Euro finals and 30,000 for the UEFA Europa League and the UEFA Nations League finals, since these regulations were introduced in 2006. After the 2007 UEFA Champions League Final, UEFA President Michel Platini stated that he wanted European Cup finals to be held at stadiums with an average capacity of 70,000 to solve security issues. The hosts for the finals between 2008 and 2013 (Luzhniki Stadium, Stadio Olimpico, Santiago Bernabéu, Wembley Stadium and Allianz Arena) all had capacities of at least 70,000, but the 2014  and 2020 host (Estádio da Luz) holds 65,000 spectators, the 2019 host (Metropolitano Stadium) holds 67,000 spectators and the 2021 host (Estádio do Dragão) holds just 50,033.