The First Five Year Plan of India was mainly based on which of the following economic growth models?

Introduction / Context:
India adopted planned economic development through Five Year Plans after independence. Each plan was inspired by certain economic models and developmental priorities. The First Five Year Plan, which started in 1951, focused heavily on agriculture, irrigation, and basic infrastructure and was guided by a specific theoretical model of growth. This question asks which growth model formed the main basis of the First Five Year Plan.

Given Data / Assumptions:

• The question is about the First Five Year Plan of India, covering the early post independence period.
• Options include the Harrod Domar model, the P C Mahalanobis model, a combination of both, the Solow model, and the Keynesian consumption function model.
• We assume familiarity with the fact that later plans evolved toward different models, especially the Mahalanobis approach from the Second Plan onwards.
• The task is to identify which model was explicitly used to frame the First Plan.

Concept / Approach:
The Harrod Domar model is an early growth model that links economic growth to savings and investment levels through the capital output ratio. It suggests that higher savings and investment rates lead to higher growth, given a fixed capital output ratio. The First Five Year Plan in India relied on this model to estimate required investment levels for target growth rates, with a strong focus on agriculture and irrigation to remove shortages. The Mahalanobis model, which emphasised heavy industry and a different investment pattern, became prominent from the Second Five Year Plan, not the first.

Step-by-Step Solution:
Step 1: Recall the chronological order of planning in India and the associated models.Step 2: Recognise that the First Five Year Plan (1951 to 1956) used the Harrod Domar type model as the analytical basis for estimating growth.Step 3: Recall that the P C Mahalanobis model was introduced and applied mainly in the Second Five Year Plan, which had a stronger emphasis on heavy industry.Step 4: Compare this knowledge with the options given.Step 5: Choose Harrod Domar model as the correct answer for the First Five Year Plan.

Verification / Alternative check:
Standard texts on Indian economic planning clearly state that the First Five Year Plan was based on a simple Harrod Domar framework, focusing on savings, investment, and the capital output ratio to achieve a target growth rate. They further explain that from the Second Plan onwards, the Mahalanobis model guided strategy with a bias toward heavy industrialisation. This clear separation confirms that only the Harrod Domar model is associated with the First Plan.

Why Other Options Are Wrong:
The P C Mahalanobis model applies mainly to the Second and later Plans and is not the basis of the First Plan. The option that claims both Harrod Domar and Mahalanobis models were equally used is misleading because the Mahalanobis strategy had not yet been adopted in the First Plan period. The Solow neoclassical growth model and the Keynesian consumption function model are important in general macroeconomics but were not directly used as the planning framework for the First Five Year Plan of India. Hence those options are not correct.

Common Pitfalls:
Candidates often memorise that the Mahalanobis model is linked with Indian planning and may incorrectly extend this association to the very first plan. Another mistake is to assume that all plans used the same basic model. To avoid such confusion, it is useful to remember that the First Plan relied on Harrod Domar, while later plans, especially the Second Plan, moved toward the Mahalanobis heavy industry strategy.

Final Answer:
Harrod Domar model formed the main analytical basis of India's First Five Year Plan.