The purpose of the inclusion of Directive Principles of State Policy in the Indian Constitution is to establish :

The Directive Principles of State Policy were incorporated to guide the State in creating a welfare-oriented socio-economic order and to secure the grand ideals of the Preamble. The Constitution’s framers expressly intended the Directive Principles to establish a welfare state in which social and economic democracy could flourish, directing law and policy toward broad social and economic justice [1]. They function as non-justiciable but fundamental guidelines that amplify the Preamble’s pledge to secure justice, liberty, equality and fraternity and to build a new social and economic order for the people [2]. Thus, the primary purpose is to establish social and economic democracy, not merely political or Gandhian democracy alone.

Sources

1. [1] https://www.mcrhrdi.gov.in/crashcourse/presentations/SG%2007-%20Directive%20Principles.pdf
2. [2] Indian Polity, M. Laxmikanth(7th ed.) > Chapter 9: Directive Principles of State Policy > UTILITY OF DIRECTIVE PRINCIPLES > p. 113