This article was originally published on November 12, 2015.In the U.S., we're bombarded by warnings proclaiming the dangers of cigarettes. But in Indonesia, these messages aren't anywhere near as widely distributed. That's led to a more-common-than-you'd-think phenomenon that looks completely shocking to Westerners: kids who smoke. And photojournalist Michelle Siu's series, Marlboro Boys , examines the Southeast Asian country's complex relationship with tobacco through the stories of its youngest smokers.According to the World Health Organization (WHO), 63% of men and about 3% of women smoke in Indonesia. But Siu explains that tobacco is woven into Indonesia's culture at many levels.Indonesia is the fifth-largest producer of cigarettes in the world, so it’s a big part of the economy," she says, "and it’s a big part of everyday life."Complicating that is the lack of regulations — and the lack of enforcement of the few regulations that do exist — around tobacco and tobacco advertising in the country. As cigarette companies began losing customers in the U.S., Siu says they started focusing their attention to countries like Indonesia. "The advertising is everywhere," Siu says. "When you go into Jakarta, there are massive billboards and it feels like you’re stepping into the U.S. in the 1950s. [Tobacco companies] could sponsor children’s sports tournaments and there are massive billboards right in front of schools."That's one reason why Siu chose to focus her series on the smoking habits of children in the country. However, she stresses that young kids smoking in Indonesia isn't the norm. "That is definitely the extreme," she says, "but the fact that it does happen...indicates that there is an issue about underage smoking and the lack of regulation in the country."According to the Centers for Disease Control and Prevention (CDC), nearly 90% of smokers in the U.S. started before age 18. About a third of those who continue to smoke will die prematurely from smoking-related illnesses, so children are especially vulnerable to the effects of smoking and its advertising.However, thanks in part to a heap of outside criticism , the situation in Indonesia is improving, Siu adds. For instance, since she originally took these photos, the country enacted laws requiring health warnings on cigarette packaging and more strict regulation of the tobacco advertising industry. Click through to see the striking photos and Siu's original captions.