NEW DELHI: The Centre on Saturday petitioned the Supreme Court challenging the Andhra Pradesh high court verdict quashing the 4.5% minority sub-quota within the 27% reservation for other backward classes (OBC) in central educational institutions. Its argument: Muslims in the OBC category are often artisans and craftsmen, who, vis-a-vis peasant communities in the category are the more backward among the backward classes.The HRD ministry’s special leave petition, which will be argued by attorney general G E Vahanvati before a two-judge vacation bench on Monday, sought an ex parte stay of the HC order to enable implementation of the minority sub-quota in admissions to Indian Institutes of Technology (IITs) in this academic session.The petition said the HC had got the core facts wrong about the government’s December 22, 2011 notification for a sub-quota. In a curious justification, the ministry argued that the 4.5% sub-quota for Muslims was essential as they were the more backward among those identified in the central OBC List.