In Hindu India, the cow is sacred and the lacto-ovo vegetarian will eat quite well.
Cows roam freely in the streets and while the flesh is not eaten, the dairy is.
Milk is used to make chai (spiced tea) and the sweetened condensed variety is used in many sweets. For the vegan or lactose intolerant, any nut or grain milk (eg almond or rice) can be substituted.
Cream forms the base for many sauces such as in dahl makhani (black lentils in cream sauce) or in a korma dish. Coconut milk can be substituted.
Ghee is clarified butter, formed by removing the milk solids. If you aren’t able to purchase this in the international section of your grocery store, you can make your own simply by heating butter on medium/low heat. A whitish film will form; these are the milk solids. Simply scoop them away and you are left with clarified/clear butter. Ghee is used in cooking and to dress freshly baked naan and roti. Vegans can use oil instead.
Paneer is unfermented cheese and comparable to cottage cheese. Again, if you are unable to find this in your local or specialty grocery store, you can make your own. How to Make Homemade Paneer
Vegans can substitute plain tofu or make a tofu paneer. Press a firm tofu to drain out as much liquid as possible. Cut into cubes and marinate in lemon juice for a few days or up to one week.
Paneer can be made into dessert, covered in sauce and mixed into dumplings.
Yoghurt is used as a cooling accompaniment to spicy Indian food. Popular applications are raita (yoghurt ‘dip’) and lassi (yoghurt drink).