It means a way of life which recognises liberty, equality and fraternity as the principles of life. These principles of liberty, equality and fraternity are not to be treated as separate items in a trinity. They form a union of trinity in the sense that to divorce one from the other is to defeat the very purpose of democracy.
Liberty cannot be divorced from equality, equality cannot be divorced from liberty. Nor can liberty and equality be divorced from fraternity. Without equality, liberty would produce the supremacy of the few over the many. Equality without liberty would kill individual initiative. Without fraternity, liberty would produce the supremacy of the few over the many. Without fraternity, liberty and equality could not become a natural course of things. It would require a constable to enforce them.
In India there is no equality and liberty and this absence has to be removed by the force of the constitution. The government of the day, Judiciary, Civil society etc, has to play a great role in ensuring social democracy in India. The major hurdle to social democracy are casteism prevalent in the society. Other hurdle is patriarchal mindset and the communal tensions created in the Independent India.