By Carie P. WATCH RELATED VIDEO Submit Heavy fog shrouds Chongqing on May 14, 2009 in Chongqing, China. Traffic congestion and pollution have worsened dramatically in Chinese cities because of the country's long-running economic expansion. Advertisement © 2017 HNGN, All rights reserved. Do not reproduce without permission. Advertisement 0 COMMENTS CLOSE COMMENT Get HNGN's Top Stories Newsletter Everyweek You have already subscribed. Thank you.