By shouldering the burden of a big chunk of global production, and
giving Shelter to half of the world’s population, currently cities play an
important role in national economies. Benefits of agglomeration in cities
have played a major role in the process of economic development of
different countries, however, the expansion of urbanization has produced
some problems including environmental and noise pollutions and traffic
problems. Therefore many of the Metropolitan residents blame the
population growth for the problems they face while urban governors have
to find an answer to the question that if there is an optimum size for their
cities, what is that size?
This essay reflects on the optimal and sustainable size of the
metropolitans in Iran and gives separate estimation for each. Due to
scarcity of statistical information this article includes five metropolitans
of Tehran, Isfahan, Mashhad, Shiraz and Ahvaz, within the time span of
1999 to 2012. This survey is based on the estimation of surplus function
including the pollution externalities. The results show that Tehran is
overpopulated to the excess of 71 percent of its optimum size, and also it
has exceeded its sustainable size by five percent. Also other four
metropolitans of Isfahan, Mashhad, Shiraz and Ahvaz have exceeded their
optimal size but they still are in their relevant sustainable limits.