written 105 times by the  lyricist, Shakeel Badayuni, before the music director, Naushad,  could approve of it; it was shot in the renowned Sheesh Mahal  (Palace of Mirrors); and in those days of sound recording, editing  and mixing, as there was no way to provide the reverberation of  sound, Naushad had Lata Mangeshkar sing the song in a studio  bathroom.