Heat mustard oil in a kadai. Add ginger paste and garlic paste and sauté till golden. Add red chilli powder, powdered mustard seeds, coarsely powdered black peppercorns, garam masala powder and salt.
Mix and sauté for half a minute. Add shalgam, gajar and gobhi. Stir and cook for one minute. Add vinegar and jaggery. Stir and cook for two minutes more.
Remove from heat and allow it to cool completely. Transfer into sterilized bottles. The achaar will be ready to eat after seven to eight days.