When they were considering Darshan Do Ghanshyam as a traditional song written by surdas, there was a possibility of them including a portion of it in the film, if not at the start practice/ blinding scenes, it could have come as one stanza where 14 year old blind Arvind sings while begging when Jamal finds him.
May be, ARR could have composed a version of it. A religious song would have added a nice touch of spiritual India. Though i concede that the guy Arvind rendered it in such a beutiful voice with touching pathos. The kid has got a voice. Hope to see him singing a full song for ARR. I know that he hasn't actually turned blind. :-) :-) :-) -- Rawat