Meaning: The production possibility curve is the curve which represents all those combinations of two commodities that can be produced with full utilization of resources in the most efficient way, which give the same level of satisfaction to a consumer. 

Properties of PPC:

1. PPC slopes downwards from left to right: It is because in a situation of fuller use of the given resources, production of both goods cannot be increased simultaneously. for example, More of Good X can be produced only with less production of Good Y.
2. PPC is concave to the point of origin: It is because to produce each additional unit of Good X, more units of Good Y will have to be sacrificed. Opportunity cost of producing every additional unit of Good X tends to increase in terms of the loss of production of Good Y. Production will act upon the law of increasing marginal opportunity cost.
3. All points which lie on the PPC are the set of combination of two goods with the full utilization of resources and efficient utilization of technology.

Railways applied a check on the occurrence of famine during colonial period by rushing food supplies from surplus areas to drought hit areas.

(i) Lack of double coincidence of wants It was a major drawback of the barter system. It was very rare when the owner of some goods or services could find someone who wanted his goods or services and possessed that goods or services that the first person wanted. No exchange was possible, if the double coincidence of wants was not there.
(ii) Lack of common measure of value In barter system, there was absence of a common unit of measurement in which the value of goods and services can be measured. In the absence of common unit, proper valuation was not possible.
(iii) Lack of standard for deferred payments Deferred payment means future payments. In barter system, it was difficult to return value in future in terms of goods of same quantity and quality. Therefore, future , payments regarding interest and loans became difficult.
(iv) Lack of store of value Due to absence of money in barter system, wealth was stored in terms of goods. Storing of goods carried some problems like cost of storage, loss of value, transfer from one place to other, etc. So, in case of commodities, it was difficult for people to store their purchasing power.
(v) Lack of divisibility In commodity exchange, difficulty of dividing the commodity has been arised. e.g. if car is to be exchanged for a scooter, then car cannot be divided. Similarly, animals cannot be divided into smaller units.

The Planning Commission which has a legacy of 65 years has been replaced by the NITI Aayog. The utility and significance of the Planning Commission had been questioned for long. The replacement seems to be more relevant and responsive to the present economic needs and scenario in the country.

NITI Aayog Evolution

The NITI Aayog was formed on January 1, 2015. In Sanskrit, the word “NITI” means morality, behavior, guidance, etc. But, in the present context, it means policy and the NITI stands for “National Institution for Transforming India”. It is the country’s premier policy-making institution which is expected to bolster the economic growth of the country. It aims to construct a strong state that will help to create a dynamic and strong nation. This helps India to emerge as a major economy in the world. The NITI Aayog’s creation has two hubs called “Team India Hub” and “Knowledge and Innovation Hub”.

1. The Team India: It leads the participation of Indian states with the central government.
2. The Knowledge and Innovation Hub: it builds institution’s think tank capabilities.

NITI Aayog is additionally creating itself as a State of the Art Resource Center, with the essential resources, knowledge, and skills that will empower it to act with speed, advance research and innovation, bestow crucial policy vision to the government and manage unforeseen issues. The reason for setting up the NITI Aayog is that people had expectations for growth and development in the administration through their participation. This required institutional changes in administration and active strategy shifts that could seed and foster substantial scale change.

Objectives of NITI Aayog

1. The active participation of States in the light of national objectives and to provide a framework ‘national agenda’.
2. To promote cooperative federalism through well-ordered support initiatives and mechanisms with the States on an uninterrupted basis.
3. To construct methods to formulate a reliable strategy at the village level and aggregate these gradually at higher levels of government.
4. Economic policy that incorporates national security interests.
5. To pay special consideration to the sections of the society that may be at risk of not profiting satisfactorily from economic progress.
6. To propose strategic and long-term policy and programme frameworks and initiatives, and review their progress and their effectiveness.
7. To grant advice and encourage partnerships between important stakeholders and national- international Think Tanks, as well as educational and policy research institutions.
8. To generate a knowledge, innovation and entrepreneurial support system through a shared community of national and international experts, etc.
9. To provide a platform for resolution of inter-sectoral and inter-departmental issues in order to speed up the accomplishment of the progress agenda.
10. To preserve a state-of-the-art Resource Centre, be a repository of research on good governance and best practices in sustainable and equitable development as well as help their distribution to participants.
11. To effectively screen and assess the implementation of programmes and initiatives, including the identification of the needed resources to strengthen the likelihood of success.
12. To pay attention to technology improvement and capacity building for the discharge of programs and initiatives.
13. To undertake other necessary activities in order to the implementation of the national development agenda, and the objectives.

 Its main function is to recommend how the Union government should share taxes levied by it with the states. These recommendations cover a period of five years. 

The commission also lays down rules by which the centre should provide grants-in-aid to states out of the Consolidated Fund of India.