One way to define a slum is a neighborhood where the buildings and land have no clear title of ownership so the people who live on that land and "own" those structures cannot legally defend their property nor is there any way for them to sell or mortgage their property, get loans from a bank to make improvements, or to get some basic services. A problem for people who live in the slums along the canal near my house is that they don't know if or when they will get evicted and then where they could go for the same rent they're paying now or to buy a house for what they would receive in compensation for the low value of their house. They surely couldn't afford anything else not far outside of the city. What they need as replacement is legal affordable housing and most likely that needs to be provided by the government. Often when the government clears neighborhoods, they will build an apartment block somewhere and give the people who lived in the cleared neighborhood an opportunity to live in the new apartment building at a somewhat affordable price.
A broader definition of a slum is where there is a lack of connection to public infrastructure like plumbing for sanitation and receiving clean water for cooking and bathing, electricity, trash collection, telecommunications, and legal status. By that definition I'm not sure there are any large slums in the city. But many of Saigon's canals have become "slumways".
But across the narrow alley from the shanties of these slums are houses with significant investment in them. Building up a home to multiple storeys signals at least some confidence in the sustainable value of their property. The row of shanty houses they face not only don't have the money to build, it's far too risky when the local police could come and tear it all down at any moment. But this shows you can live a meter away from a slum yet still be quite well off and not worried about the property value of your house being affected by the fact that you're right next to a slum.