How to use oven to incubate Dahi?
You can use oven as an insulated box, and use electric bulb to keep the cavity warm.
Buy an extension chord that has a light bulb fixture on one end. Put in a 75 Watt bulb. Place it on the top rack of an oven cavity of the range. Place Dahi mix on the bottom Rack. Turn on the light bulb. Close the door. It will get your oven temperature to about 105º F. The good range for active culture is 100º F - 120º F. Check you temperature. All Ranges are different. You may have to go to a lower or higher wattage bulb.