Wash and peel the green mangoes. Slice or grate the flesh of the green mangoes, discarding the seed. Try to remove as much of the flesh as possible. Set aside.
In a large heavy bottomed pot add sugar, salt, sliced ginger, garlic, raisins, and dry dates. Add 1 ½ cups of water and bring this mixture to a boil.
Once the mixture comes to a boil, turn the heat to low and let it cook for about 10 minutes. The sugar will dissolve as the mixture cooks.
Add the grated or sliced raw green mango (kairi) and cook for around 30 – 35 minutes. Keep heat on low, and stir the mixture every few minutes. As the mixture cooks, it will thicken and the consistency will turn jam like. The cooking time will differ depending on the ripeness of the green mango used. If the green mangoes are more unripe, the cooking time will increase and if the green mangoes are on the riper side, the cooking time will reduce.
Add whole red chilies, followed by nigella seeds and vinegar.
Cook for another 5 minutes, and then turn off the stove. Taste and add additional salt, if required.
As the mixture cools, it will thicken a little more.
Once the mixture has completely cooled, it can be kept in jars or an air-tight container in the fridge. If proper care is taken, the chutney can be kept in the fridge for about 3 months. It’s best to store the chutney in small jars, using one jar at a time. Make sure to use a clean dry spoon when taking out the chutney.