Dangerous smog levels choke China's Baoding

China issues its highest level smog alert as world leaders arrive in Paris for a Climate Summit. Al Jazeera's Adrian Brown reports on the devastating impact of industrialisation in China's most polluted city of Baoding. Subscribe to our channel http://bit.ly/AJSubscribe Follow us on Twitter   / ajenglish   Find us on Facebook   / aljazeera   Check our website http://www.aljazeera.com/