Take ripe mangoes in a mixer and puree them. Set aside.
Take sugar and water in sauce pan. Heat to dissolve, bring to boil and switch off the flame.
Add in lemon juice and mango puree. Mix well. Store this syrup in a jug and chill it. This is your mango lemonade syrup.
Now to make lemonade. Take a glass pour some of the syrup, add some water and mix well. Serve immediately.