Indian food without garlic and onions is trying to be religiously inclusive. Jainism is a popular religion in India, which teaches nonviolence. Included in that belief is the idea that nothing should be harmed, even plants. As such, they seek to avoid eating any vegetables that are harvested by killing the plant. Onions and garlic both require that their plants be killed, so Jains try to avoid those. Instead, their food often contains hing, a smelly spice that hasn’t really caught on in the west. I haven’t tried it, but hose that have say that once cooked, hing somewhat resembles the taste of onions and garlic.