What Are the Causes of the Delays in Real Estate Construction?

i read a beautiful chapter in tim harford's book, which talks about how the elevator is also a mass transit system when it comes to skyscrapers. And what we're looking at is the second part of frictions and supplies. The first is policyis like a fesi, which don't allow housing to be built. Then there are regulatory delays or approval delays that means that whatever's being built gets slowed down drastically. There is litigations, which are another cause of major frictions in inhousing supply.