Very few houses are built entirely of one material. For example, only dense forest areas where wood seems plenty are piles, floors, walls and roof all made of wood. A concrete house has a concrete frame and slabs, but walls are often infillings of bricks or glass or metal sheeting, etc. A brick house usually means only walls are of brick, but floors and roofs are of other materials, and so on. So when you think of a mud house, do not expect to make the entire house of mud (though it is a possibility!). Bricks use a lot of fuel to burn them; stone needs quarrying, shaping and transporting. Concrete needs a great deal of energy to make the cement and then skilled labour to turn these materials into concrete. But in many parts of the world mud is right there on the site as an old, well-tried wall building material. All that is needed is the human-power to convert the ground on which you stand into a wall to surround and protect you.
All over the country mud of some sort or other is found. Even if the surface soil is unsuitable for wall building, there may be suitable mud beneath, or by adding stabilisers your mud may be made suitable. Compare this situation with the burnt brick industry. Comparatively few areas have suitable mud for the purpose of burning mud into a burnt brick. So the ideal is to find mud on your own site. If this is not possible, bring it from as short a distance as possible, or find the nearest stabiliser available and then you only have to transport that to your site.
One of the greatest problems to face during the next fifty years is that of energy. The pressure of this problem will be less if we can make use of energy-free materials as much as possible. One of India's major tasks is to provide homes for at least 25 million families who have no home. If we are to build with burnt bricks and concrete and steel, etc., we add to this vast energy problem, and to the overall cost of housing millions of families. If only we will apply our twenty-first century know-how and techniques to our age-old mud, we can solve this housing need without adding to this energy problem. So, don't just say, "Mud is old fashioned." You can make it the latest fashion-mode!