The initial proposal and subsequent release of the First Five-Year Plan in December 1951 generated considerable enthusiasm throughout the country. Individuals from diverse backgrounds, including academics, journalists, government officials, private sector employees, industrialists, farmers, and politicians, actively engaged in extensive discussions and debates surrounding the plan. The enthusiasm for planning reached its zenith with the commencement of the Second Five-Year Plan in 1956 and persisted to some extent until the Third Five-Year Plan in 1961. The implementation of the Fourth Plan was scheduled to commence in 1966.

Pandit Jawaharlal Nehru, was himself a supporter of which model of the economy?

Socialist

After India's independence, numerous individuals in India were greatly influenced by the Soviet model of development, which embraced a socialist approach. This included leaders from the Communist Party of India, the Socialist Party, and influential figures like Nehru within the Congress party.  Consequently, a consensus emerged during the national movement, with the following key points:
Nationalist leaders recognized that the economic objectives of an independent Indian government should diverge from the narrow commercial functions of the colonial government.
It was widely acknowledged that the responsibility for poverty alleviation and social and economic redistribution primarily rested on the government's shoulders.