How to minimise the flow of atmospheric heat through concrete roof in to the house?

In India where atmospheric heat is very high, and the roof of top most floor is normally concrete, heat filtering into the floor below through roof is enormous. How to reduce the amount of heat that filters in through Concrete roofs.

Answers:
DIY has a web page that talks about insulation boards and they can also be used underneath a cement roof to cool down a attic space. see the link below....

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