Cube raw mangoes with skin.Smear 2 tsp salt and turmeric and keep in direct sunlight for 2 days.
Dry roast mustard,fenugreek,dry red chillies and methi seeds and grind to a fine powder.Set aside.Discard any water from the mangoes after 2 days.Add methi, sauf,chopped ginger and garlic and chopped dry chillies or chilli flakes.Add oil and dry roasted masala.Oil should just cover the mangoes.Add dry roasted and ground masala as needed.Add vinegar; hing, turmeric,kashmiri red chilli powder,red chilli powder,salt and little sugar to taste.Keep in direct sunlight for 4-5 days.
Check softness of mangoes.Keep the pickle in a wide mouthed glass jar and keep the jar in sunlight for 7 more days. Mango pickle is done.Serve with rice,roti or paratha.
