ahhh dont use mr salim's tactics here.
There is NO such thing called lower or higher casts in Islam.
all are equal and this is manifested by Hujj wherein all Muslims from all corners of the world irrespective of their creed, colour, status (which you are talking about by bringing this economic status definination of sharafia or otherwise even it has NOTHING to do with casts. ) are together at one place and same and equal.
whereas in Hindu cast system there is clear Untouchability where low casts Hindus barred from visiting some temples, where low cast Hindus are considered inferiors.
So its better to act upon Albert's saying Little knowledge is dangerous thing .