The condition here is :
We must make some building unit that acts as a temperature reducer and can retain lower temperature to the inner walls of a building which has an outside temperature of more than 42 degrees Celsius. This hereby reduces the use of cooling machines such as air conditioners , coolers etc. This material can be made cost effective by using natural materials instead of synthetic substituents.
I would like to bring a change in the chemical composition or chemical bonding of the binding material or the building blocks that we use in construction (of walls especially) instead of adding any extra material like that of in a cavity wall. This can be any chemical that can be added to the binder as an admixture or can be applied as a coating after construction of walls .