For
It can solve overpopulation and save land space.
Against
Costs, safety, and psychological effects make it risky.
Anonymous excerpts, translated where noted.
“Dense settlement can limit land consumption while allowing people to maintain relatively normal lives.”
“Building compactly lets housing, transport and public services serve more people on less land.”
“Underground infrastructure is expensive to build, inspect and repair compared with systems that remain accessible above ground.”
“Living underwater means every structural failure, power loss or evacuation problem becomes immediately life-threatening.”