>>Start with Sub-saharan Africa At least for that part, it's quite inexpensive and easy to do Just stop doing something, stop helping in any way shape or form, and you'll see, africa will revert back to the stone age on its own for the most part Before the european/western intervention in africa, through various humanitarian programs, starting with vaccination campaigns (yes) drastically reducing infant mortality, food assistance programs, etc... Africa's population was stable, under 100000 (yes) if memory serves, for centuries https://pic8.co/sh/rd4ddu.gif https://en.wikipedia.org/wiki/Demographics_of_Africa >>The population of Africa **has grown rapidly over the past century[1]** and consequently shows a large youth bulge, further reinforced by a low life expectancy of below 50 years in some African countries.[2] Total population as of 2020 is estimated at more than 1.3 billion,[3] with a growth rate of more than 2.5% p.a. The total fertility rate (births per woman) for Sub-Saharan Africa is 4.7 as of 2018, the highest in the world according to the World Bank.[4] The most populous African country is Nigeria with over 206 million inhabitants as of 2020 and a growth rate of 2.6% p.a.[5] https://en.wikipedia.org/wiki/Demographics_of_Africa#History