Select firm green mangoes, give them a good wash, and pat them dry.
Remove the seeds from the mangoes and cut them into small pieces. Then, liberally season with salt.
To get rid of extra moisture, let the mango chunks dry in the sun for a few hours.
Before combining, heat mustard oil until it smokes and then let it cool somewhat.
Combine dried mango chunks with mustard seeds, chili powder, and turmeric.
Cover the mixture with cooled oil, swirling thoroughly to coat all of the ingredients.
Before eating, let it marinade for a week in a sterile jar.