of ancillary or subordinate legislative functions, or, what is fictionally called, a power to fill up details. The legislature may, after laying down the legislative policy confer discretion on an administrative agency as to the execution of the policy and leave it to the agency to work out the details within the framework of policy……………….. 12. The question whether any particular legislation suffers from excessive delegation has to be decided having regard to the subject matter, the scheme, the provisions of the statute including its preamble and the facts and circumstances in the background of which the statute is enacted…….It is also well settled that in considering the vires of subordinate legislation one should start with the presumption that it is intra vires and if it is open to two constructions, one of which would make it valid and the other invalid, the courts must adopt that construction which makes it valid and the legislation can also be read down to avoid its being