A central business district (CBD) is the profitable and business centre of a city. In bigger cities, it is often identical with the city’s “financial district”. Physically, it often coincides with the “city centre” or “downtown”, but the ideas are discrete: many cities have a dominant business district situated away from its profitable or cultural city centre or downtown, or even several CBDs at on one occasion. The form and kind of a CBD almost always carefully reflect the city’s past. Cities with tough conservation laws and maximum building height limitations to recollect the character of the historic and cultural core will have a CBD pretty a distance from the centre of the city. Increasing urbanisation in the 21st era have developed megacities, particularly in Asia, that will often have multiple CBDs distributed across the town area. It has been said that downtowns (as understood in North America) are therefore theoretically distinct from both CBDs and city centres. No two CBDs look similar in terms of their three-dimensional shape, however certain symmetrical patterns in these areas are frequent throughout many cities due to the nature of centralised commercial and trade activities.