this Court laid down the following propositions: (1) that the management can retrench its employees only for proper reasons, which means that it must not be actuated by any motive of victimisation or any unfair labour practice, (2) that it is for the management to decide the strength of its labour force, for the number of workmen required to carry out efficiently the work in his industrial undertaking must always be left to be determined by the management in its discretion, (3) if the number of employees exceeded the reasonable and legitimate needs of the undertaking it is open to the management to retrench them, (4) workmen may become surplus on the ground of rationalisation or economy reasonably or bona fide adopted by the management or on the ground of other industrial or trade reasons, and (5) the right to affect retrenchment cannot normally be challenged but when there is a dispute about the validity of retrenchment the impugned retrenchment must be shown as 'justified on proper reasons, i.e., that ' it was not capricious or without rhyme or reason.