Peel the kairi / raw green mangoes and place with 1 litre of water in a stainless-steel pot.
Bring to a boil, and then cook on low simmer till the kairi / raw mango is soft. This will take about 20 – 25 minutes.
Remove the kairi / raw mangoes and remove as much as pulp as possible, discarding the seed. Blend the kairi / raw mango pulp with water using an immersion blender. Or let the mixture cool, and then blend in a blender.
Cook on low heat till the sugar dissolves, and the mixture thickens. This will take about 20 minutes.
Turn off the heat, and then add the roasted cumin powder along with the black salt. Stir through.
Let the mixture cool, and then store in the refrigerator in clean bottles. Alternately, the aam panna / kairi sharbat can also be frozen in trays. Once the panna / sharbat is frozen, then the ice cubes can be kept in a ziploc bag.
Place 2 – 4 tablespoons of the aam panna / kairi sharbat in a glass and add cold water. Top off with ice cubes and serve cold. Start off with 2 tablespoons of concentrate and adjust to personal taste. Mint leaves and/or lemon juice can be added to give a different taste, and for garnish.