Containerization means the increasing use of the containers as a support for freight transportation. It involves processes where the containers are increasingly used because it either substitutes cargo from other means of transport or it is adopted as a mode supporting freight distribution ,the reason being that a large number of transport systems are able to handle containers. Both inter modal transportation and containerization are mutually connected, self strengthening and depend on a set of driving forces linked with technology, infrastructures and management. One of the major issues were the different sizes and dimensions of containers used by shipping lines, which were a source of much confusion in compiling container shipping statistics. The loading could involve different volumes since different box sizes were involved. The usage of containers has helped in a faster movement and a standardization of loads. The container has substantially contributed to the adoption and diffusion of inter modal transportation which has led to a lot of changes. Through reduction of handling time, labor costs, and packing costs, container transportation allows a considerable improvement in the efficiency of transportation. Thus, the importance of containers is not what they are but what they enable. A major change in freight transportation could not have taken its current form without containerization. It can be rightly said that the maritime sector should have been the first mode to pursue containerization. It was the means of transport less used because of the time taken to load and unload the vessels.

Containerization permits the mechanized handling of cargoes of different types and sizes that are placed into boxes of standard sizes. Thus goods that took days to be loaded or unloaded from a ship can now be handled in a matter of minutes. Containers are either made of steel (the most common for maritime containers) or aluminum (particularly for domestic) thus helping in the flexibility. Another reason for greater movement of the container is through the implementation of International Standards Organization (ISO) within 10 years of its introduction. Because of this ,large container sizes and specifications have been put in use. The most commonly used container size is however the 40 foot box, which in its 2,400 cubic feet which carry on average 22 tons of cargo. However, transporting cargo in a 20 ft container is usually 80% of the cost of transporting cargo in a 40 ft container because irrespective of the size a 20 ft container requires the same amount of inter modal movements even if it takes about half the space. A significant share of international containers are either owned by big shipping lines. In few countries , a large amount of domestic containers of 53 foot are also used. Double stacking of containers on railways (COFC: Containers On Flat Cars) has doubled the capacity of trains to haul freight with minimal cost , thereby improving the competitive position of the railways with regards to loading freight for long-haul shipments. The maritime containers are used in international trade, and other types of containers are found in the airline industry. Increased labor costs and the slowness of loading , that require a very rapid turnaround, made the industry very receptive to the concept of a loading unit of standard dimensions designed to fit the specific shape. shipping management courses in kerala