Mr. Goswami, learned Addl. Advocate General, Assam, on the other hand, has argued that Rule 11(3) merely provides that the vacancies to be filled up by way of promotion of Sub-Engineers to the post of Assistant Engineer (Mechanical) shall not exceed 30% of the total cadre strength. There is no mandate under the Rules which requires that 30% of the post must be reserved for being filled up by way of promotional departmental candidates. Under the circumstances, submits Mr. Goswami, this writ petition is mis-conceived. The learned Addl. Advocate General has further argued that the notification by means of which promotion given to the petitioners with prospective effect, was issued on 11-06-2002. Notwithstanding the same, they had approached this Court by filing a writ petition only in the year 2011. Therefore, this writ petition is hit by the principles of delay and laches and is liable to be dismissed on such count alone.