It's essentially this but with a few additions.
http://www.epicurious.com/recipes/food/views/yogurt-marinated-grilled-chicken-366453
Cumin, deghi mirch, tandoori powder, paprika, liquid smoke, soy sauce, ginger, garlic, salt, pepper, olive oil, yogurt. I'm not sure if the yogurt is the difference because my mom gets some culture every time she goes to India from the bakery in our home town and brings it to the states and makes yogurt every other day at home. Basically a little portion of it is set aside as the seed for the following batch. Haven't found yogurt that tastes nearly as good or creamy in America.