On December 22, 2021, the Chinese Ministry of Ecology and Environment (MEE) published the HJ 1229-2021 Guidelines for Screening of Priority Assessment Chemical Substances (hereinafter referred to as Guideline), and it will take effect on January 1, 2022. The Guideline stipulates the scope of chemical substances subject to the screening for priority assessment, screening principles and procedures, technical requirements for screening, and requirements for report preparation, etc.