London — Nairobi has become one of the best cities in sub-Saharan Africa for international business people to live and work in, states a new study released this week.

The city was ranked sixth out of 30 in the Mercer Business "Quality of Living" survey. Although it was ranked behind Cape Town, Johannesburg, Lusaka, Dakar and Blantyre, it was way ahead of its neighbours, Dar-es-Salaam, Khartoum and Addis Ababa.

There are 39 criteria used to rank the cities. These include political, social, economic and environmental factors as well as personal safety and health, education, transport and other public services.

Nairobi's ranking is up one place from last year. It has also been ranked among the top 150 cities for the business community worldwide, ahead of such cities as St Petersburg and Moscow in Russia, Belgrade in Yugoslavia, Bangalore, Madras and Mumbai in India, Havana in Cuba and Jeddah in Saudi Arabia.

Eighteen of the bottom 30 cities in the world - according to the quality of living survey - are in sub-Saharan Africa. Dar-es-Salaam is one of them.

The only two African cities in the top 100 are Cape Town and Johannesburg in South Africa. The top two cities are Zurich and Geneva in Switzerland.

Mercer's index aims to help international firms to establish how suitable cities are for their staff.

"When multinational companies set up expatriate assignments, they have to provide attractive reward packages to compensate employees for any negative changes to their quality of living," said Ms Yvonne Sonsino of Mercer.

"Moving abroad can be a big upheaval for expatriates and their families, particularly if they are in cities with low living standards and facing political unrest or terrorist threats. Mercer rates Baghdad as the worst city in the world.