Well friend as you know social disparity in India is well established already.  The concept of  UBI is that everyone be it rich or poor or middle class are entitled to it.  In such a scenario it only increases disparity because if one is already rich and gets a basic income means he would spend it on some luxury while the poor will stick to basic need.  The class gap will just widen. Other factors like past savings, ancestral wealth will help middle and rich class even if there is lack of jobs. If UBI is established as a limited concept then it is no more universal and a limited concept will always have exclusion errors like the present PDS etc.