were held to be free from bias, discrimination and under the exigencies of the situation then existing to be just and proper. On the basis of those judgments it cannot be urged that this Court has left to the option of the authorities concerned whether to invite tenders or not according to their own discretion and to award contracts ignoring the procedures which are basic in nature, taking into account factors which are not only irrelevant but detrimental to the public interest. 28. Philanthropy is no part of the management of an undertaking, while dealing with a contractor entrusted with the execution of a contract. The supply of the directories to public in time, was a public service which was being affected by the liberal attitude of the MTNL and due to the condonation of delay on the part of the UIP/UDI. There was no justification on the part of the MTNL to become benevolent by entering into the supplemental agreement with no apparent benefit to the MTNL, without inviting fresh tenders from intending persons to perform the same job for the next five years. Public authorities are essentially different from those of private persons. Even while taking decision in respect of commercial transactions a public authority must be guided by relevant considerations and not by irrelevant ones. If such decision is influenced by extraneous considerations which it ought not to have taken into account the ultimate decision is bound to be vitiated, even if it is established that such decision had been taken without bias. The contract awarded for the publication of the directories had not only a commercial object but had a public element at the same time i.e. to supply the directories to lakhs of subscribers of telephones in Delhi and Bombay, every year within the stipulated time free of cost. In such a situation MTNL could not exercise an unfettered discretion after the repeated breaches committed by UIP/UDI, by entering into a supplemental agreement with the Sterling for a fresh period of more than five years on terms which were only beneficial to UIP/UDI/Sterling with corresponding no benefit to MTNL, which they have realised only after the High Court went into the matter in detail in its judgment under appeal.