Heat a pan on medium heat and add cumin seeds, carom seeds, fennel seeds, black pepper corn, yellow mustard, big cardamoms, cloves, small cardamom.
Roast well till aroma starts coming turn off the heat and let it cool down completely.
Once cold add masala in a grinder and make a fine powder of it.
Wash and dry lemons, then remove the sides cut the lemon into desired size and remove all seeds.
Transfer the lemons into a bowl, add asafoetida, turmeric powder, red chilli powder and powdered masala.
Next add rock salt and mix well.
Now squeeze 3-4 lemons in it mix again, fill in clean dry glass bottle.
Cover the top with a cotton cloth and secure it with a rubber band.
Keep in sunlight for 4-5 days and mix twice a day while shaking it properly.
Once achaar is ready store it in clean, dry glass container.