Place the coriander seeds, cumin seeds, and aijwan into a spice grinder. Grind coarsley.
Transfer to a mixing bowl.
Add the red chilli flakes, chaat masala, black pepper, salt, garlic powder, gram flour, and food color. Mix well.
Add the egg and lemon juice. Mix well until a thick paste forms.
Transfer the fish cubes into the prepared marination.
Mix with gentle hands until all the pieces are evenly coated.
In a deep wok, heat the oil to medium high.
Add a few pieces of the fish at a time, and fry for 2-3 minutes on each side. Do not overcrowd the wok.
Using a slotted spoon, remove the fried fish and place on a cooling rack.
Serve with mint raita or tamarind chutney.