It's probably a combination of incompetence and a whole lot of corruption. Sub contractors cutting corners, not using all the ingredients for the cement, stuff like that. The one thing that separates developing countries from industrialized ones is the level of corruption. They are all corrupt but developing countries, anywhere, Asia, Central and South America permeates all through society and unfortunately in physical structures.
Inspectors are a combination of incompetence and corrupted. Paid off to give a good report.