I can refer to two decisions of the Apex Court in relation to exercise of controlled discretion and quote relevant passages from them. The first would be the case of Suman Gupta and Others Vs. State of Jammu & Kashmir and Others, and what their Lordships said in paragraph 6 of the reports:–
6. … … … After considering the matter carefully, we confess, we are unable to subscribe to the view that the selection of candidates for that purpose must remain in the unlimited discretion and the uncontrolled choice of the State Government. We think it beyond dispute that the exercise of all administrative power vested in public authority must be structured within a system of controls informed by both relevance and reason–relevance in relation to the object which it seeks to serve, and reason in regard to the manner in which it attempts to do so. Wherever the exercise of such power affects individual rights, there can be no greater assurance protecting its valid exercise than its governance by these twin tests. A stream of case law radiating from the now well known decision of this Court in Mrs. Maneka Gandhi Vs. Union of India (UOI) and Another, has laid down in clear terms that Art. 14 of the Constitution is violated by powers and procedures which in themselves result in unfairness and arbitrariness. It must be remembered that our entire constitutional system is founded on the Rule of Law, and in any system so designed it is impossible to conceive of legitimate power which is arbitrary in character and travels beyond the bounds of reason. To contend that the choice of a candidate selected on the basis of his ability to project the culture and ethos of his home State must necessarily be left to the unfettered discretion of executive authority is to deny a fundamental principle of our constitutional life. We do not doubt that in the realm of administrative power the element of discretion may properly find place, where the statute or the nature of the power intends so. But there is a well recognized distinction between an administrative power to be exercised within defined limits in the reasonable discretion of designated authority and the vesting of an absolute and uncontrolled power in such authority. One is power controlled by law countenanced by the Constitution, the other falls outside the Constitution altogether. Proceeding from there it is evident that if the State Government desires to advance the objective of national integration it must adopt procedures which are reasonable and are related to the objective. In this Age of Reason, all law must measure up to that standard, and necessarily so also must all executive acts. Viewed in this context, the claim of the State Government in these cases that the nature of the objective and the means adopted to serve it entitle it legitimately to vest in itself an absolute power in choosing candidates for nomination cannot be allowed to prevail. It is incumbent on the State Government to adopt a criterion or restrict its power by reference to norms which, while designed to achieve its object, nevertheless confine the flow of that power within constitutional limits. We are not convinced that an adequate system of standards cannot be devised for that purpose. … … …
 Then I would refer to the case of S.G. Jaisinghani Vs. Union of India (UOI) and Others, , and what is said in paragraph (14) of the reports:–
(14) In this context it is important to emphasize that the absence of arbitrary power is the first essential of the rule of law upon which our whole constitutional system is based. In a system governed by rule of law, discretion, when conferred upon executive authorities, must be confined within clearly defined limits. The rule of law from this point of view means that decisions should be made by the application of known principles and rules and, in general, such decisions should be predictable and the citizen should know where he is. If a decision is taken without any principle or without any rule it is unpredictable and such a decision is the antithesis of a decision taken in accordance with the rule of law. (See Dicey–“Law of the Constitution”–Tenth Edn., Introduction ex). “Law has reached its finest moments,” stated Doughlas, J. in United States vs. Wunderlich, (1951) 342 US 98V , “when it has freed man from the unlimited discretion of some ruler. … Where discretion is absolute, man has always suffered”. It is in this sense that the rule of law may be said to be the sworn enemy of caprice. Discretion, as Lord Mansfield stated it in classic terms in the case of John Wilkes, (1770) 4 Burr 2528 at p. 2539 “means sound discretion guided by law. It must be governed by rule, not by humour: it must not be arbitrary, vague, and fanciful.”
Apex Court in the case of Ex-Capt. Harish Uppal Vs. Union of India (UOI) and Another, and what their Lordships said in paragraph 30 thereof:–
30. … … … Nobody or authority, statutory or not, vested with powers can abstain from exercising the powers when an occasion warranting such exercise arises. Every power vested in a public authority is coupled with a duty to exercise it, when a situation calls for such exercise. The authority cannot refuse to act at its will or pleasure. It must be remembered that if such omission continues, particularly when there is an apparent threat to the administration of justice and fundamental rights of citizens i.e. the litigating public, courts will always have authority to compel or enforce the exercise of the power by the statutory authority. The courts would then be compelled to issue directions as are necessary to compel the authority to do what it should have done on its own.
Again it can be said that in Francis Bennion in his “Statutory Interpretation”, 1984 edition, says at page 683.
Unnecessary technicality: Modem courts seek to cut down technicalities attendant upon a statutory procedure where these cannot be shown to be necessary to the fulfillment of the purposes of the legislation.