Wash the shrimp thoroughly under running water. Drain well and pat dry with paper towels. Put in a bowl and add ½ teaspoon of the salt and the lemon juice. Stir well, then marinate for 15 minutes.
Put the turmeric, chile powder, the remaining ½ teaspoon salt, the ginger paste, and garlic paste in a bowl, and stir well. Add to the marinated shrimp and stir well.