Add salt and sugar to yogurt and whisk till well mixed. Keep it in the refrigerator till use.
Mix boiled potatoes, sprouted moong, salt, half teaspoon of red chilli powder, chaat masala.
Put the yogurt in a muslin cloth kept over a bowl. Gather the edges and squeeze tight to get a smooth mixture.
Break the puris a little on one side, fill it up with the potato filling, dip them in the yogurt and place them on a plate.
Alternatively you can also keep the puris on the plate and then pour the yogurt over leaving aside some for topping at the end.
Put green chutney, sweet tamarind chutney, sev, remaining red chilli powder, roasted cumin powder, coriander leaves, pomegranate pearls over the puris and finally dribble the remaining yogurt on top.