Dar es Salaam is Tanzania's most important city for both business and
 government. The city contains unusually high concentrations of trade 
and other services and manufacturing compared to other parts of 
Tanzania, which has about 80 percent of its population in rural areas. 
For example, about one half of Tanzania's manufacturing employment is 
located in the city despite the fact that Dar holds only ten percent of 
Tanzania's population. Downtown Dar es Salaam includes many small 
businesses, many of which are run by traders and proprietors whose 
families originated from the Middle East and Indian sub-continent — 
areas of the world with which the settlements of the Tanzanian coast 
have had long-standing trading relations.
Dar es Salaam has a problem with slums. According to a United Nations
 estimate, 70 percent of Dar es Salaam's population lives in informal 
settlements. The divisions in Tanzania's lop-sided economy, with a tiny 
super-rich elite and a vast poor majority, are reflected in its main 
city. The poorer residents crowd into dilapidated downtown areas or 
sprawling slums, many without running water or basic services. Their 
rich counterparts can choose among US$1 million beachside mansions in 
the city's posh northern districts.(
http://www.bbc.co.uk/news/magazine-18655647)
Located on a natural harbour on the Indian Ocean, it is the hub of the Tanzanian transportation system as all of the country's main railways and several highways originate in or near the city.
Its status as an administrative and trade centre has put Dar es 
Salaam in position to benefit disproportionately from Tanzania's high 
growth rate since the year 2000 so that by now its poverty rates are 
much lower than the rest of the country. The Benjamin William Mkapa Pension Tower with more than 21 stories is the tallest building in the city and the country.
 Dar es Salaam and other Tanzanian cities have had, in the past few 
years, a major construction boom, despite a much higher demand for 
electricity, which is rationed around the country. Since 2000, Dar es 
Salaam had a face-lift, but the major infrastructural problems remain. 
Among those problems are an outdated transport infrastructure and power 
rationing, which continues to badly affect the Tanzanian economy. Air Tanzania, the national airline, has its head office in Dar es Salaam.