Existing drainage systems in many colonized Asian cities are over hundred years old. These were constructed according to European urban norms and standards existed at the time. Today these cities have become prone to flash floods even in a very low precipitation event. Establishing proper urban drainage systems is vital for these cities to avoid flash flood hazards. However, this was not an attainable target for many Asian cities mainly due to solid waste blocking drainages. Still many Asians dump their solid waste in to the nearest drain. This review examined the causal factors behind flash flood events to identify hidden crucial factors behind drainage failures in Asian cities. Drainage systems of colonized Asian cities were constructed following a Gridiron patterned urban form. But present urban form is completely different from Gridiron pattern due to unplanned urbanization, making the colonial drainage designs which were constructed according to an urban structure existed hundred years ago, utterly ineffective. Therefore, a need exists for novel down to earth drainage designs which are compatible with present urbanscape of densely populated Asian Cities in the developing world.