Wash the Mustard seeds and sundry for 2 days. There must not be any moisture.
Wash the Mangoes and dry them using a kitchen towel.
Peel the skin and cut the mangoes into small pieces. discard seeds.
Now sprinkle half of the salt over the mangoes and put those over a perforated bowl for 15 minutes.
After 15 minutes, the Mangoes will start releasing the moisture. That liquid is to be discarded as well.
Take Mangoes along with both types of Mustard, Green Chili, and Garlic in a Mixer grinder and make a coarse paste.
If required, make the paste in two or three batches.
Once done, take the paste in a big "Earthen Pot" and pour mustard oil over the paste.
Add sugar and salt as well, and using a dry spoon, mix everything.
Now cover the pot with a clean cloth and keep it in the room for 7 days.
You do not need to place the same under direct sunlight.
After seven days, open the cloth and transfer the Aam Kasundi to a sterilized Jar.
Keep Aam Kasundi in the refrigerator. This is to be consumed within one month of making.