By the BBC's
Joseph Warungu

The port city of Dar es Salaam was the capital of Tanzania before the shift inland to Dodoma. The name Dar es Salaam is derived from Arabic, meaning a safe port. Like many other towns on the east coast of Africa, it's a hot, humid city.

Like the weather, the political atmosphere is rarely cool in Dar. This is because Dar is the centre of everything. For years the authorities have wanted to move all government head offices to Dodoma in central Tanzania, but the goal has never been realised.

So all political parties, plus the National Electoral Commission are based here. Indeed all four presidential candidates are registered to vote in Dar, and will held their final rallies in the city.

This multi-racial, cosmopolitan city once housed about one million people. Today the number has tripled with Tanzanians from all corners of the country converging on Dar in search of a better livelihood.

Many people have made Dar es Salaam their second home and they are not in a hurry to leave - hence the expansion of the town and the pressure on politicians to better accommodate and serve the ever-growing population.

It is this mix of people from all kinds of ethnic, religious, and cultural backgrounds that make the politics of Dar so interesting and at times fluid. In the last election in 1995, Dar was one of the places that witnessed ugly incidents of election violence.

Tanzanians have nicknamed Dar es Salaam "bongo" which is Swahili for brains. You need a sharp brain to survive in Dar.

The pace of life here is far too fast. Politicians too need an even sharper brain, because - unlike rural Tanzania - here they are dealing with an educated population that will not easily swallow grandiose election promises.

The politicians also know that Dar is the place to watch your steps and your words, as this is where all the newspapers and radio and television stations are based.

On Friday night, trouble erupted after an opposition CUF rally in Dar, and police moved in with tear gas to disperse the crowds.

The fight for political control in Dar can reach such frightening heights and many city dwellers are only hoping and praying that Sunday's election will pass off quickly without incidents so that Dar es Salaam can live up to the meaning of its name - safe port.