Flour is blended with water to arrange the dough for chapatti. whereas making chapatti, it's first baked on both sides on a tawa or griddle.it is then put instantly on the flame of teh fuel range.The component in contact with the flame produces water vapour and carbon dioxide insde the chapatti. When teh steam and carbon dioxide attempt to escape, the chapatti bulge. If there is a hole anywhere in the chapatti, the gases get away in the course of the hole and the chapatti does now not bulge.
an identical action occurs when puris are fried in oil.