Hanoi is experiencing rapid urbanisation with many roads being extended and new roads built. As a result, tiny and strangely-shaped houses have sprouted up on the leftover lands.
Super-tiny and strangely-shaped houses have been a problem in Hanoi for a long time. In 2018, Hanoi authorities ordered a review and possible seizure of super tiny and narrow houses for public use such as gardens but the plan hasn't been realised.
As the old tiny houses still haven't been dealt with, new houses appeared along with new road projects.
Some photos of the houses:
Tiny and strangely-shaped houses in Hanoi