1) Grind mustard seeds to a coarse powder. Cut limes into eight pieces. Slit green chilies and cut them into half inch long pieces.

2) Mix powdered mustard seeds, turmeric powder and salt with green chillis and lime pieces.

3) Transfer this to a sterilized glass bottle or an earthenware jar. Pour oil on top and shake the bottle well. Cover with a muslin cloth and keep it in an airing place.

4) Stir the contents of the jar for for few days, at least once a day.