trump has not spoken much about his policy, so there's not much for markets to react to. >> linda hong in singapore for us, thank you very much. now for the latest from the united nations climate summit. >> the big topic is how to reduce carbon dioxide emissions while the united states has long been one of the world emitters of greenhouse gases. an american city once known for its smoggy skies shows it's possible to cut pollution. pittsburgh. pennsylvania is undergoing a transformation. as dw found out. >> this is the old image of pittsburgh. a city of steel and coal, with the smokestacks don't stop them in smoke and the lights had to be left on 24 hours a day because the smoke blocked out the sun. today's reality is a different one. they cleaned up their act, instead of heavy industry, banks, and high-tech companies are proving jobs for a growing population. more than 13,000 pittsburghers are employed in the clean energy sector alone, companies such as ever power, which operates wind farms and is developing projects in other states. for co-founder, pittsburgh is the perfect place were