Kibera, Africaâs largest urban slum, is based three miles from Nairobiâs city centre - a city that will almost double in size in the next 10 years. Kibera is estimated to house up to one million of its people, most of whom earn less than $1 per day.  Lydia - a young woman born and raised in the slum, who asked The Telegraph to withhold her surname - now lives in a house on its border. The social worker, who currently works with American exchange students, remembers how she began to see its limitations. Initially, there was comfort in Kibera's strong sense of community as she grew up in its Laini Saba village. "We took each othersâ problems as our own, regardless of our inability to solve it. Kids required less to be happy. We had no need for expensive toys as we made stuff from whatever was available. I remember I would make dolls from thread and plastic bags."  But as you grow up, "you are opened to the other sides of life and interact with other people. Then you begin to realise life has more and in order to have a fulfilling life you need an environment that is conducive for growth."  It was dangerous at night due to the lack of lighting, and disease outbreaks were common as government rubbish collectors would not collect waste from the slums. She remembers that "it was easy to escape problems by engaging in drugs, and other substance use and other illegal activities."  Increasing urban populations may make the matter worse, driving more people into slum housing.  There are several initiatives, both government and community led, to help improve the quality of life for slum dwellers. The Kenyan government is building apartment blocks near Kibera to relocate residents, while projects such as Map Kibera - formed by young Kiberans - aim to open up slum space to the wider community and prevent slums from becoming a "blank spot" for outsiders.  There are opportunities to come from such urban poverty. The African Population and Health Research Center has highlighted how residents of slums are younger than average and have higher birthrates. With the greater proportion of working age people that arises from this, there are better chances of economic sustainability.  If this is combined with the right government intervention, providing education and health infrastructure, investment in poorer areas can increase, which can higher wages and better housing improvement.  There has to be investment in slums, according to the UN, to prevent them from becoming no-go zones of informal development. "Slum upgrading" is a process promoted by its settlement programme, whereby local authorities work with communities to gradually improve living conditions.  The UKâs International Development Minister, Justine Greening, has previously said: "Economic development needs to be hand in hand with lifting Africans out of poverty and bad jobs."  Lydia agrees. She says poverty-related issues like unemployment and crime will continue as populations rise. According to her experiences of Kibera, she thinks a bottom-up approach is needed.  "Lots of people in the slums, especially those that missed education, should be engaged in programs that allow them to get skills that could make them self-dependent or engaged in self-employment, since the current number of available jobs is less than the demand for jobs"
As Africa's population looks set to quadruple over the twenty-first century, The Telegraph digs into the data to reveal the opportunities - and challenges - facing a fast-changing continent