How accurate is this film? (slight spoilers)

I have no clue whether this was filmed in HK or China. Either way, how accurately does this film portray street life in it's respective country? I have the feeling it may be a little bit exaggerated, like the scenes in the schools for example and the drug peddling. I mean, would much hardcore criminals deal with kids that age apart for maybe distribution, you know street kids are usually deemed expendable. (I'm specifically talking about Panadoll and her relationship with a hardcore criminal).

Another thing is that when you look at these street kids homes, which they themselves raid, they look pretty well off, compared to the likes of real street kids where I come from or the slums of Brazil for example (quite accurately portrayed in films like Onibus 174, City of God, Elite Force etc..)