First cut stems of mango then wah it properly.
Put mangoes with skin and 1 cup water in pressure cooker.
Now cook it for 3-4 whistle on high flame. Switch off the gas stove then cool down naturally.
Peel off mangoes ; scoop out pulp and keep it in grinder jar.
Add cooked sour water, sugar, cumin powder, white - black salt,mint leaves in grinder jar and grind it medium to high speed for 2 minutes. This consistency must be smooth paste.
You can store this paste in a jar and keep it in fridge. This could be lasts for 7 days.
Whenever you want to have this drink ; take 1/4 part pulp and 3)4 part water,ice cubes in a glass and then mix very well.
Cool - cool aam - panna is ready for serving.