After a video of a chain-smoking 2-year-old Indonesian boy, Aldi, went viral last year, piling up 13 million hits on YouTube, Indonesian authorities sent the toddler to rehab to break him of his pack-or-two-per-day habit. ABC's 20/20 went to the fishing village only to catch up on Aldi, now 4, and found that he was far from the only child lighting up on a regular basis. Here, a guide to the country's "epidemic" of tobacco-addicted kids.

Aldi isn't the only smoking baby?

Sadly, no. Approximately a million children under the age of 16 smoke, according to ABC News. Worse yet, one third of Indonesian children try smoking before the age of 10. In some startling examples, the 20/20 crew met 2-year-old Chairul, who is fed cigarettes by his grandfather. Then there was 7-year-old Maulana, living in a nearby town, who blows smoke rings while his mother looks on.

Why is the habit so widespread among kids?

Cigarettes are incredibly cheap in Indonesia — costing a "mere" dollar per pack. And there is no age limit for buying tobacco, so it's perfectly normal to see a child purchase a single cigarette for 10 cents. It probably doesn't help that cigarette advertisements are plastered on school walls.

So, who is at fault? 

Parents who freely give children cigarettes take some of the blame. But critics of big tobacco companies say they are responsible, too. Some cigarette makers have long taken advantage of the absence of restrictions in foreign countries, including those that don't prohibit them from like specifically targeting young people. "The tobacco industry rides roughshod over public health interests" in Indonesia, says Mary Elizabeth Williams in Salon.

Is anyone trying to help the situation?

It's unclear. Philip Morris International responded to the viral video and 20/20 investigation with an email saying it supports "strict regulation of tobacco products," and encourages the Indonesian government to introduce laws that would ban cigarette sales to minors. Unfortunately, anti-tobacco legislation has died in parliament.

What about Aldi? Is he still smoking?

He has reportedly quit, though he says he misses it. But Aldi reportedly bargains with his desperate mother, getting her to buy him toys as a reward for keeping his lungs smoke-free. Aldi's mother says she wishes she had never let him start, and admits that she caught him lighting up recently.