Papadum is a thin crispy round disc type cracker that is almost always in front of you at an Indian table. Typically made from peeled black lentil flour and is fried or traditionally dried out in the sun.
You can see above the rooftops the drying process is carried out in the daylight and hot scorching sun does the job. I won’t mention the Delhi pollution but for beginners who aren’t accustomed to basic level Indian airborne bacteria – stay cool and try to be prudent when selecting foods in any restaurant. Indian lifestyles is different to what you might expect.
In certain parts of India raw papadum are dried and not roasted and the dough is often flavored with seasonings such as chili, cumin, amchur, garlic, etc. Sometimes baking soda or lime is also added to maintain a steady and consistent dough that doesn’t rise too much.
When you mix a base (baking soda) you get a reaction of bubbles and carbon dioxide forms creating the leavening in your dough.
PS: in the photo you can see rose petals drying on the rooftops cement roofs, which is used for rose waters.