According to a recent survey there are about 40,000 Chinese restaurants and around 5,000 Indian restaurants in United States. I feel Indian restaurants can attract more customers if they offer vegan dishes such as Tofu burji , seitan biryani (seitan is wheat-based meat), and using tofu in palak paneer.
Atlanta has few good Indian vegetarian restaurants. Whenever we are in Cumming area, we go to Sri Krishna Vilas. The food is amazing! So far, I have eaten Thali , Bhel Puri and Samosa Chat. My son loves masala dosas in this restaurant. http://skvilas.com/sri-krishna-vilas-cumming/
Whenever, I'm in this restaurant, I feel I'm in India! People who love Indian food should eat in Sri Krishna Vilas.
Amma's Kitchen is another simple restaurant in Alpharetta, GA. We tend to go to Amma's Kitchen whenever we go to Hanuman Mandir. Amma's Kitchen is pure Vegetarian eatery. They have variety of Doasa, idly , Poori Channa. The food is simple and not oily. This is great eatery if you want to try traditional dishes of Andhra Pradesh(Southern state of India).
Amma's Kitchen also sells some tradition snacks and sweets. Sweets such as mysore pak and rava ladoo contains ghee(clarified butter). If you are a Vegan, avoid any dish which has the words ghee, paneer(Indian cheese), dahi (yogurt) .
Amma's Kitchen website is not working. I found an interesting article about Amma's Kitchen http://clatl.com/atlanta/specific-spice-at-amma-kitchen/Content?oid=2240647
Chennai Express is another eatery which is becoming popular in Alpharetta area. This is also pure vegetarian eatery. They have variety of dosas, idli, Chinese dishes, south-indian tradition rice dishes such as Tamarind rice (puliogare), and Tomato rice .
They also have coupe of dishes made with ghee such as ghee pongal, and ghee masala dosa. If you are a vegan, just make sure you mention not to add ghee to dosa or any dish.
Chat Patti is another popular eatery. If you like Indian snacks and chats, you ought to visit Chat Patti.