http://www.newsweek.com/mystery-source-ozone-depleting-substance-tracked-eastern-china-1191345

The mystery source of an ozone depleting chemical substance has been tracked to eastern China, with scientists finding “significant ongoing” emissions of the potent compound carbon tetrachloride coming from the Shandong province.

The discovery raises questions about the source of the substance. In 2010 the production of carbon tetrachloride was banned under the Montreal Protocol, so finding out how and why it is turning up in the atmosphere is extremely important.