Places generally along the South Freeway (I-45), and south of the Ship Channel, including Clear Lake, Deer Park, Freindswood, the Hobby Area, League City, Pasadena, Santa Fe, South Houston, and Texas City.
Philosophizing notwithstanding, Austin's guidance basically shuts jobs down, period, unless they fall within one of six fairly specific exceptions (public works, for example). Linkage:
http://austintexas.gov/sites/default/files/files/Order 20200324-007 - Stay Home - Work Safe.pdf
AIA Austin is trying to get an exception for general residential and commercial construction, but didn't get it as of noon Friday: https://www.aiaaustin.org/aia-austin-and-covid-19
Anecdotally, it looks like a lot of projects and borderline "exempt" businesses here are shutting down for the duration - probably something to do with wanting to keep people healthy. Until there is a blanket order, people are going to have to research locality by locality to know what the rules are.
Sorry for the slow reply, but I've been socially distant (actually, answering clients' phoned and emailed questions and moving most of my office to my house).