is enunciated with sufficient clearness or a standard is laid down, the courts should not interfere with the discretion that undoubtedly rests 20 1951 SCC 568. Civil Appeal No. 7708 of 2014 & Ors. Page 12 of 17with the legislature itself in determining the extent of delegation necessary in a particular case. 25. Birla Cotton 7J (supra) refers to Raj Narain Singh v. Chairman, Patna Administration Committee21, wherein this Court held that an executive authority can be authorised by a statute to modify either existing or future laws but not in any essential feature. What constitutes an essential feature cannot be enunciated in exact terms. However, it was held that modification could not include a change in policy, since the ‘essential legislative function’ consists of the determination of legislative policy and its formulation as a binding rule of conduct. In the context of Section 17(2)(viii) and Rule 3(7)(i), we are of the opinion that main legislation does not fall foul of the