If you accept reservation for Scheduled castes / tribes, then why not for other backward groups, and hence the argument in this thread.
According to Wiki on the Mandal Commission, these are the following criteria.
Mandal Commission - Wikipedia, the free encyclopedia
(i) Castes/classes considered as socially backward by others.
(ii) Castes/classes which mainly depend on manual labour for their livelihood.
(iii) castes/classes where at least 25 per cent females and 10 per cent males above the state average get married at an age below 17 years in rural areas and at least 10 per cent females and 5 per cent males do so in urban areas.
(iv) castes/classes where participation of females in work is at least 25 per cent above the state average.
edit] Educational
(v) Castes/classes where the number of children in the age group of 5–15 years who never attended school is at least 25 per cent above the state average.
(vi) Castes/classes where the rate of student drop-out in the age group of 5–15 years is at least 25 per cent above the state average..
edit] Economic
(viii) Castes/classes where the average value of family assets is at least 25 per cent below the state average.
(ix) Castes/classes where the number of families living in kuccha houses is at least 25 per cent above the state average.
(x) Castes/classes where the source of drinking water is beyond half a kilometer for more than 50 per cent of the households.
(xi) Castes/classes where the number of households having taken consumption loans is at least 25 per cent above the state average.
Also known as “Creamy layer,” this criteria of separation is ignored by the government which is known as the most controversial issue of reservation.
So according to the Mandal commission, there does not seem to be anything that excludes Muslims as a religious group.
I come back to my orignal point, if you give reservation on the basis of jati, then you open a pandora’s box.