Legal basis: Xi's Notice on Establishing Real Estate and Real Estate Linkage Mechanism to Promote the Stable and Healthy Development of Real Estate Market II. Strengthening the management of housing transactions (IV) Residents who move from outside the city to buy commercial housing or second-hand housing in the housing restricted area of this city must settle in this city for 1 year and pay social insurance or personal income tax continuously for 12 months (excluding veterans and approved talents). (5) In the restricted housing area, the online signing of commercial housing sales contracts has been filed for 5 years and the certificate of immovable property rights and the certificate of second-hand housing immovable property rights have been processed for 5 years before listing and trading.