Chinese fans are watching the Olympics on TV, puffing on cigarettes in a smoke-filled bar. Suddenly, when the Chinese team scores, they crush out their cigarettes and jump up to cheer. 

'Love China,' says a message on the screen. 'Increase patriotism even more. Love a smoke-free Olympics.' 

That public-service advertisement was funded by the Bill & Melinda Gates Foundation, targeting TV viewers in China during the Olympics. It's part of a new initiative to cut tobacco use in the country that's home to 350 million smokers and more than a third of the world's cigarette production. 

While it was once common to see thick clouds of smoke in China's trains, restaurants and even offices, the government has joined the effort to crack down on smoking. 

'I think this is a magic time for people to get behind the anti-tobacco work,' Bill Gates said last month in launching the initiative. 'It will be a tough fight and a long-term fight, but a very important one.' 

Smoke-Free China A Marathon Challenge