BEIJING, Jan. 2 (Xinhua) -- China has vowed to build a national unified rating system for nursing homes by 2022 amid efforts to improve services of these facilities, the Ministry of Civil Affairs said in a guideline released Thursday.

Nursing homes across the country are encouraged to file for ratings on a voluntary basis, said the guideline, which also noted the ratings will follow a unified procedure and have the results recognized nationwide.

The guideline asked provincial authorities for civil affairs to designate a department for the rating service or determine a third-party rating agency through open bidding.