Take raw mango pieces, mustard seeds, salt, green chillies, asafoetida and turmeric powder in a mixer and grind them together in to coarse paste.
In a bowl add whisked yogurt and raw mango paste from above step. Blend them by stirring with ladle.
Heat a seasoning pan adding all the seasoning ingredients one after the other. As the mustard seeds splutter and pop, transfer the seasoning to yogurt curry.
Raw mango yogurt curry is ready to serve as rice side dish.
Notes
I have used raw mango pieces with skin, if you prefer you can peel the skin off.
If your raw mango is very tangy, then use only 1/2 cup. Mine was not so tangy, so used 1 cup.
Always use fresh, not so sour yogurt to prepare this curry.