They had amazing cities. Harappa and Mohenjo-Daro are the best known, with dense, multi-story homes constructed out of uniformly sized bricks along perpendicular streets. I mean, this wasn't some ancient world version of Houston. More like Chicago. This means they must have had some form of government and zoning, but we don't know what gave this government its authority. Cities were oriented to catch the wind and provide a natural form of air conditioning. And they were clean.