Cut the mango (with less fibre) into small piece and with the hands, squeeze the juice from it. Strain the juice through a sieve and keep aside.
Heat the water and add sugar and citric acid to it. When the sugar completely dissolves, remove from fire and sieve through a thin cloth. Allow it to cool.
Add the mango juice in the sugar solution. Stir it well. Dissolve potassium meta bisulphate in some water and mix it with the squash. Keep it in an air tight bottle.