Extract juice from all the citrus fruits including the blood oranges in a citrus juicer or squeeze by hand. Makes about 1-1/2 cups juice. For the Jal jeera, I have used 1-1/2 cups water for every 1/2 cup juice.
Roast the cumin seeds in a skillet until fragrant and crackling without burning. Grind to a powder in a mortar and pestle and keep aside.
Mix 1-1/2 cups cold water to 1/2 cup juice. Sprinkle roasted and freshly ground cumin, freshly ground black pepper, sea salt, black salt, jaggery and dried mint crushed between your fingers and thumb.
Taste and adjust spices, salt and jaggery as needed or add more juice or water to suit your taste. Jaggery neutralizes salty, sour and hot tastes. So adjust accordingly.
Serve cold garnished with a sprig of fresh mint.