The U.S. Department of the Treasury's Office of Foreign Assets Control (OFAC) has released the names of individuals placed on a list known as the Specially Designated Nationals and Blocked Persons List. This designation means their property and interests in property within the U.S. are blocked, and U.S. citizens are generally restricted from conducting transactions with them. The document specifically mentions Shanghai Saint Logistics Limited and describes its involvement and linkage to MAHAN AIR, which has been designated under U.S. sanctions aimed at counter-terrorism efforts. The information can be found on the OFAC website.
Simple Explanation
The U.S. Treasury has named a company called Shanghai Saint Logistics Limited on a special list because they did something that the U.S. doesn't like, so now they can't do business in the U.S., and people in the U.S. can't trade with them.