The government of Prime Minister Sanae Takaichi approved an ordinance Tuesday that outlines requirements for becoming a designated secondary capital in the event of a large-scale natural disaster in the Kanto region, and is designed to address an overconcentration of population and resources in Tokyo.

Of the 47 prefectures, only Hokkaido, Aichi, Osaka?and Fukuoka meet the necessary conditions. All four are making preparations to submit their proposals to the central government.

Speaking to reporters Tuesday, Chief Cabinet Secretary Minoru Kihara said the requirements for being designated a secondary capital were objective standards based on available statistics and figures, as well as parliamentary deliberations during which proponents argued for the necessity of a certain population level and economic scale in order to fulfill a core function of being a decentralized economic zone.