Translation:There are not many people on the street.
This is a small thing, but "on the street" sounds strange to me (though not necessarily wrong). I would almost always use "in the street" for people or things literally in the roadway (which I assume the Chinese means). I would "on the street" to refer in a slightly figurative way to homeless people, back alley drug dealers, etc.
I think this comes down to colloquial preference; where I'm from, "on the street" sounds perfectly natural and "in the street" sounds a bit strange, haha....
The sentence sounds to me like 'in the streets' should be accepted as well.