Background and challenges to implementation:
The Shanghai Regulation on Smoking Control in Public Places was enacted in 2009, but DSRs were allowed in some indoor places, making the protection for Shanghai's 24 million residents in Shanghai ineffective. Opportunities to amend the law arose in 2016, however, there was no consensus among policymakers in terms of DSRs. Public awareness about the ineffectiveness of DSRs in preventing secondhand smoke exposure was low, and the public was generally indifferent about this issue.

Intervention or response:
To increase public support for 100% smoke-free law, Campaign for Tobacco-Free Kids and the Center for Social Media Research of Peking University conducted social media monitoring from March to October 2016, listening to what Shanghai residents cared about, how they talked about issues that were important to them, whom they listened to, and what their knowledge and attitudes were regarding secondhand smoke. Based on the listening, CTFK together with tobacco control partners designed and implemented social media strategies and tactics, such as a Shanghai-style E-poster campaign to instill pride among Shanghai residents, a running event to appeal to health-conscious people, and a flash mob featuring a local favorite singing group to reach young people.

Results and lessons learnt:
These tactics resonated with the Shanghai residents and won their support for the 100% smoke-free policy. The topic of Shanghai smoke-free law generated 15 million views and 13,000 comments. Public support increased from 40% in March of 2016 to 73% in October of 2016.

Conclusions and key recommendations:
Supportive public opinion is important for the adoption and implementation of tobacco control measures. In order to reach the right people at the right time with the most insightful contents in the most relevant style, social listening was essential. Future tobacco control advocacy efforts in China and other countries can learn from the experience in Shanghai.