Agility level of any organisation portrays the degree of flexibility of the organisation in responding to customer needs. Hence, knowledge of agility level assumes its importance for developing the competitive strategies for any organisation including the manufacturing firms. In this line monitoring the level of agility and flexibility in a manufacturing organisation could be considered to be an important element for meeting the business objectives. However, proper evaluation of this agility metrics becomes deceptive to define owing to its vague nature and application in non-manufacturing related systems. In this regard an attempt has been made in this research to develop agility index of 3 types of plants. The results of this study revealed the Polyethylene plant has the highest agility index of 9.51 out of the three case plants. The results also revealed that the agility index of the Olefins plant is 7.32 and that of the Polypropylene plant is 6.37. Plants with a high agility index reflects its higher degree of agility level.