Directive Principles of State Policy (DPSP) are a set of guidelines included in the Indian Constitution to direct and guide the government in establishing a just, equitable, and welfare state. The purpose of the inclusion of DPSP is to establish social and economic democracy in the country. Let's understand this in detail:

Social democracy:
- DPSP aim at the establishment of a social democracy in India.
- The principles laid down in DPSP are based on the socialist philosophy that advocates equality, social justice, and the welfare of the people.
- The DPSP directs the state to work towards the elimination of social and economic inequalities, provide equal opportunities for all, and promote the welfare of the weaker sections of society.

Economic democracy:
- DPSP also aims at establishing economic democracy in India.
- The principles laid down in DPSP direct the state to work towards a just and egalitarian economic system that ensures a decent standard of living for all citizens.
- The DPSP directs the state to promote the welfare of the people by providing adequate means of livelihood, equal pay for equal work, and opportunities for economic development.

Social and economic democracy:
- The inclusion of DPSP in the Indian Constitution aims at establishing social and economic democracy in the country.
- This means that the state has a responsibility to ensure social and economic justice, equality of opportunity, and the welfare of the people.
- The DPSP directs the state to work towards the establishment of a just and equitable society where every citizen has equal rights and opportunities.

In conclusion, the purpose of the inclusion of DPSP in the Indian Constitution is to guide and direct the government in establishing social and economic democracy in the country. The principles laid down in DPSP aim at ensuring social and economic justice, equality of opportunity, and the welfare of the people.

Directive Principals of State Policy is contained in part - iv of the constitution and is non-justiciable in nature.
Through these principles the makers of the constitution strived to make the holder of the political power more obliged to the public at large. Therefore, any policies which aimed at bringing welfare to the entire population it must be socially oriented as well as economically viable from the states point of view.
At the timing of framing of directives principles of state policy India was not economically sound to implement each and every policy required at that particular time. However, to make state realise their duties constitutionally, they were added by the framers with a view that they would become justiciable like the Fundamental Rights after India attains a economically sound status. Hence, DPSP under part-iv is strived to establish a social and economic democracy where policies are framed for welfare of people at large and again no one shall be left behind from enjoying schemes implemented by a particular state due to his/her economically backward status.