Kolkata, in general, is not a particularly violent city. Bengalis tend to be a peace-loving sort, more interested in their culinary pursuits and intellectual discourses than fist-fights or roadside brawls or outright murders. It is a city of adda and art.
That is not to say that these things do not happen. Crime, after all, is fairly rampant everywhere. But you hardly see it happening – well, a lot of people, at least, pass their lives in relative peace without watching a crime unfold right in front of their eyes. Perhaps many more simply look the other way and walk away the moment they realise a crime is in progress.