In developing countries, the emerging mega cities face a number of interlinked issues, such as, increased flow of trading activities (particularly in the coastal cities), expansion in manufacturing and service sectors (because of a relatively developed infrastructure). As a combined effect of these factors there is a significant increase in population from within and neighboring countries. The situation aggravates even further when the huge influx of population exerts enormous pressure on limited physical and social infrastructure of a city. The obtained situation is thus observed with increased environmental degradation and significant rise in poverty levels.
The coastal city of Karachi which is the largest city of Pakistan is now considered as one of the ten biggest mega cities in the world and appears as a classic case of such type of expansion in its size of population. As per the last population census of 1998 in the country, Karachi had a population of 9.8 million (though controversial). In absence of the new population census which was due in 2008, different estimates suggest that the current population size of Karachi city would be around 20 to 25 million. Along with the population growth, an average income level of its inhabitants has also caused upward shifts in consumption expenditures. The simultaneous raise in production of solid waste, as an outcome of improved standards of living and increased business activities, has impaired the city’s institutional capacity to properly dispose off and recycle the solid wastes. In the obtained situation, the remaining part of solid waste is disposed off and recycled by the private sector.