Add only half the amount of sugar water and check the consistency as is should not be very thin. Strain sugar water also to remove any impurities from it.
Sieve it so as to remove fibres ( if you want pulpy frooti you can avoid this step). Once mangoes cool down blend it with hand blender or in a mixer. Let the pressure cooked mangoes and sugar water cool down completely Heat only till the time sugar has completely dissolved, we don't have to make sugar syrup so no need to boil much. Mean while keep water for boiling, when boiled add sugar and stir it. Pressure cook with half cup water for 3 whistles.
Wash, peel and dice both raw and ripe mangoes.