CAATSA Implementation Act of 2021 This bill requires the President to impose property-blocking sanctions with respect to Nord Stream 2 AG, the entity that operates the Nord Stream 2 pipeline designed to carry natural gas exports from Russia to Germany. Furthermore, before the President terminates such sanctions or removes the application of these sanctions to a particular person, the President must report to Congress the reasons for such an action and comply with other related requirements. These requirements, which currently apply to certain other sanctions, include (1) requiring specified waiting periods after submitting the report before the President may take the action, and (2) prohibiting the President from taking the action if a joint resolution of disapproval is enacted.