Yes, it is necessary to have public sector due to its contribution to the economic development in India.
The role of public sector/government is as follows.
(i) It ensures rapid economic development.
(ii) It promotes redistribution of income and wealth.
(iii) It develops industries which require huge investment.
(iv) It ensures balanced regional growth.
(v) It prevents concentration of economic power.
(vi) It generates resources for development.
(vii) It promotes import substitution.
(viii) It generates employment.
(ix) It helps in development of small-scale industries.