Atta is the flour used to make most South Asian flatbreads, such as chapati, roti, naan and puri. Most atta is milled from the semi-hard wheat varieties, also known as durum wheat, that comprise 90% of the Indian wheat crop, and is more precisely called durum atta.
Hard wheats have a high content of gluten (a protein composite that gives elasticity), so doughs made out of atta flour are strong and can be rolled out very thin. Indian wheat are mostly Durum wheat, which are high in protein but less in “bread forming gluten” so the bread when baked with this flour does not rise as well and tend to be dense.