What is a good onion substitute?

Earlier this week, the wholesale price of onions touched Rs. 70 per kg in India. When you compare that with the price of a kilo of potatoes—the other favourite vegetable used in almost every Indian dish—there is a difference of Rs. 49. Unfortunately, while both potato and onion are roots, they cannot substitute one another while preparing a meal.
With the wholesale prices touching Rs. 70 per kg in Mumbai, located in the western part of the country, chances are that vegetable vendors will be selling onions at Rs. 120 per kg to earn Rs. 50 from their sale. This makes the vegetable almost unaffordable for a large number of people, and even those who can afford to buy it will think twice before making the purchase. 
While there are many who firmly believe that you cannot substitute an onion with anything else, others say that there are alternatives. For city resident Manav Parekh, cauliflower works as an alternative. “While it isn’t a substitute for onions, it does leave a lovely crunchy flavour,” he says.
US-based chef Joan Campanella, who later adopted the name Yamuna Devi after converting to Hinduism, wrote a book titled Lord Krishna's Cuisine: The Art of Indian Vegetarian Cooking, which presents an interesting take on the subject. None of the dishes in the book have onion as a staple ingredient. Instead of onions, Yamuna Devi has used spices for providing the perfect balance.
Reema Prasanna, a digital marketing specialist, food blogger, and baker says that one shouldn’t worry too much about the rise in the price. “The problem lies in perspective. Nothing should be indispensable to your mind. If you don't have onions for a while, deal with it. Find your peace in curries made of dry fruits, cream, ground spices or coconut. If you are a remotely half-decent cook, you will know how to work in the kitchen even when onions are missing. People have to stop making such a big deal out of it and work with what they have instead of lamenting over what they don't,” she says. 
Bangalore resident Nandita Iyer, whose food blog Saffrontrail has a large following, says that there are tonnes of Indian recipes that don’t use onions. “A number of traditional Tamil Brahmin recipes, Bengali vegetarian recipes and Jain recipes do not use onions,” she says, adding that having dishes that do not require onions in the ingredients helps. 

Substitutes for onion:
•    You can use a combination of ginger, tomatoes and vegetable puree for thickening the gravies.
•    Cabbage, beet and crushed radish can be used as options.
•    If you don’t have a choice, you can always opt for dried and chopped onions available in the supermarket. While they don’t match up to the regular onions, they can serve as an economically viable alternative. 
•    Asafoetida adds a complex and intense flavour to a dish. Be careful with the quantity though, as pure asafoetida granules carry a strong flavour and a little goes a long way.