In the table above, when the population of a country increases from 50 lakhs to 100 lakhs and 150 lakhs, the per capita income of that country also increases from one thousand to two thousand and from two thousand to three thousand respectively. Thus, the state where per capita income increases with increasing population is the state of underpopulation. 

When the population is 200 lakhs or 2 crores, the per capita income is Rs. 4,000, which is the maximum per capita income. Therefore, this is the state of optimum population. If the population increases beyond this, the per capita income starts to decrease. 

For example, in the table, when the population is 2 crore 50 lakhs, 3 crores, and 3 crore 50 lakhs, the per capita income decreases to Rs. 3,000, Rs. 2,000, and Rs. 1,000 respectively. This state is the state of overpopulation.

According to this above figure, 2 crore population is the optimum population. In this state, per capita income is maximum or Rs. 4,000. When the population is less or more than this, the per capita income is lower, for example, when the population is 150 lakhs, the per capita income is Rs. 3,000. 

Similarly, when the population is 250 lakhs, the per capita income is also Rs. 3,000. Therefore, point D in the figure is the point of optimum population. The state from point A to D is the state of underpopulation, and the state from point D to E is the state of overpopulation.

The size of the optimum population is not always constant. When resources, means, and technology increase, the size of the optimum population also increases, and when there is a decrease in resources, means, and technology, its size also decreases. 

The development of production technology and economic resources increases the size of the optimum population because more population is needed to utilize more resources. This theory makes only economic factors the main basis. 

From an economic point of view, a small population may be the optimum population in any country, but from a political point of view, a larger population may be more suitable.

Criticisms of the Theory of Optimum Population

1. Difficult to Determine Optimum Population
   The theory states that the optimum population is the population size at which per capita income is maximized. However, in reality, it is difficult to accurately determine the exact population level where this occurs. The optimum population is not fixed and changes over time due to technological advancements, economic conditions, and resource availability.

2. Ignores Non-Economic Factors
   The theory mainly focuses on economic factors such as per capita income and resource utilization while ignoring important non-economic factors such as social welfare, political stability, and environmental sustainability. A country may achieve high per capita income but still face issues like unequal wealth distribution and poor living conditions.

3. Assumption of Fixed Resources
   The theory assumes that the natural resources of a country are fixed, which is not always true. Resources can be discovered, developed, or depleted over time. Technological progress can increase resource efficiency, making it possible to sustain a larger population than previously thought.

4. Neglects Population Composition
   The theory considers the total population size but does not account for the age structure, skill level, and productivity of the population. A country with an optimum population in terms of numbers may still struggle economically if it has a high dependency ratio (too many children or elderly people) or a workforce lacking necessary skills.

5. Difficult to Apply in Policy-Making
   Even if a country determines an approximate optimum population, controlling population growth through policies is challenging. Population growth depends on multiple factors, including birth rates, migration, cultural beliefs, and government policies. Implementing policies to achieve the optimum population is complex and may face resistance from society.