Globally, informal settlements are increasing – here's what we need to do about it.

 Slums and other informal settlements house around 1.1 billion people worldwide.

According to a new analysis, upgrading informal settlements would allow millions of children to attend school and raise some countries' GDP by more than 10%.

Land tenure, increasing microloans, and assisting low-cost housing start-ups are some of the solutions.

People are living in slums and other informal settlements in greater numbers than ever before. But this isn't simply a worldwide problem; it's also a global opportunity.

In the last 20 years, the number of people living in slums or other informal settlements has increased by 165 million, bringing the total to about 1.1 billion.

Families without access to inexpensive housing are forced to live in inadequate housing with limited access to sanitation, power, and safe drinking water. Residents of informal settlements frequently lack security of tenure or land rights, and are constantly threatened with eviction.

Consider Freetown, Sierra Leone, one of the world's most populated cities. Up to 60% of the over 1.2 million population live in a patchwork of informal settlements built on unstable soil prone to flooding, fires, and landslides. This amount of unplanned expansion resulted in catastrophe in 2017, when a disastrous landslip killed over 1,000 people. It is believed that approximately 40% of housing complexes in Freetown have been developed in medium- or high-risk regions due to a lack of urban planning, a lack of governmental monitoring, and a chronic lack of affordable housing.