Turn into Tatu City on the outskirts of Kenya's capital, Nairobi, and it feels like entering a different world.

Even the country's most reckless drivers are transformed, slowing to a crawl and not tossing trash out the window - thanks to surveillance cameras and rigorously enforced penalties for speeding and littering.

For the 5,000 people who have moved into Tatu, a "startup city" that welcomed its first residents four years ago, the ruthless upholding of such rules makes the place appealing. "Tatu has more law and order than other places," said Valerie Akoko, a digital content creator who moved in two years ago. "I've never seen Tatu City dirty." Situated on 2,023 hectares, Tatu City aspires to be what its name suggests: a city, privately owned, that its designers hope will eventually have a population of 250,000.

It is already home to 88 businesses employing 15,000 people.