Or maybe rank the countries you know about?
It's super easy to get drugs in China. I don't know about Singapore. I've never lived there. I lived in China for a year and a half. When my dad came to see me he wanted to get high. He was in a place he'd never been to before and talked with like 2 people and found his pot. This was on his first night back in China. And he doesn't even speak Chinese.
Essentially no countries don't have a drug problem, but that depends on how you define it, you won't be able to find drugs in most countries without looking for them to some degree, but places like China or Singapore are probably some of the hardest places to get drugs, but if someone really wants some they will always be able to get some, so it will never be impossible to find some, as someone will always supply because there's so much money to be made.
Does not exist, unless there are no humans there. Drugs are in our nature, and a part of everything that we consume, on a daily basis. It just so happens that governments have decided to play morality police, and decided which ones should be so socially acceptable that they are in our food chains at enormously unnatural levels, and which ones should be socially unacceptable and illegal, which is often based on how much money can be made when they are legal vs illegal.
the North Pole