The Supreme Court on Thursday rejected applications of the Union Government and Maruti Udyog Limited (MUL) seeking an extension of the deadline for implementing stricter emission norms in private non-commercial vehicles in the National Capital Region(NCR).A three-judge bench, comprising Chief Justice A S Anand, Justice B N Kirpal and Justice V N Khare, however, said they would clarify their April 29 order, which fixed the deadline with regard to other aspects including vehicles running on Compressed Natural Gas(CNG).