There seems no such a hotel you want in Tianjin.
I think you can find other nice hotels in Tianjin and stay there. Then you can have dinner outside in a Vegetarian restaurant. I didn't see any special Indian Vegetarian restaurant in Tianjin, but i know some nice vegetarian reataurant, such as 并蒂莲素食 at the cross corner of Changdedao and Kunming Lu. If you are interested, you may go there to have a taste.