One aspect of the built environment is housing.
Recently, popular housing materials, such as treated lumber, synthetic insulation and certain paints (to name a few) have been exposed as harmful to both the environment and the inhabitants of the houses. There is no dispute over this issue; anyone who cares to ask will find that treated lumber releases the preservatives and poisons which it was soaked in over a predictable period of time.
This is where "alternative construction" comes in. Some would say it's quite an odd name, considering that the strategies used to conserve energy and materials have been documented for millennia in some cases.
Adobe, wattle and daub, mud-brick, rammed earth, earth bag and straw bale housing construction is alive and well. In many instances the houses are less expensive to build and maintain, healthier to live in and more sturdy and reliable than those made from "conventional" materials.
Much of the trouble with acceptance in the mainstream comes from advertising. If a company knows that the average customer is perfectly capable of building their own house of readily available materials for a fraction of the market price, then that company must convince unaware consumers that the "alternative" option simply doesn't exist.
Of course, with many of these same companies sitting on planning boards, alternative construction has been given quite an unfavorable reputation in some localities.