Combine the gram and plain flour in a bowl. Add salt, chilli powder, ground cummin, turmeric and the ghee or oil and mix until well blended. Mash the bananas and mix with finely minced green chills and sugar. Add to the flour and knead to a smooth dough, adding a little water if necessary. Divide the dough into 16 portions and roll into wafer-thin circles. Cook on a greased griddle or in an iron frying pan, turning once, to brown both sides.