Original sentence: The economic health of Downtown Manhattan, which by itself is the third-largest business district in the United States (after Midtown Manhattan and the Chicago Loop) has been seriously imperiled by the attacks, in which 30% (28.7 million sq
Edited sentence: The attacks created a unique challenge to Downtown Manhattan, which by itself is the third-largest business district in the United States (after Midtown Manhattan and the Chicago Loop) since 30% (28.7 million sq