The New International Economic Order (NIEO) was a set of proposals put forward by developing countries in the 1970s with the aim of restructuring the global economic system in a more equitable and balanced manner. The NIEO sought to address the growing disparities between developed and developing countries and to promote economic growth, social progress, and self-determination for all nations.

Key Principles of NIEO:
1. Economic Sovereignty: Developing countries demanded the right to determine their own economic policies and to have control over their resources. They argued for the nationalization of key industries and the establishment of state planning mechanisms to promote economic development.

2. Resource Redistribution: One of the central objectives of the NIEO was to address the unequal distribution of resources between developed and developing countries. Developing nations called for the establishment of a New International Economic Order Fund to provide financial assistance and technology transfer to support their development efforts.

3. Trade and Investment Reforms: Developing countries sought to reform international trade and investment rules to provide them with greater access to markets and to protect their infant industries. They called for the removal of trade barriers, fair pricing for commodities, and the regulation of multinational corporations.

4. Debt Relief: Developing countries argued that the burden of external debt was preventing them from achieving sustainable development. They called for debt cancellation, lower interest rates, and more favorable repayment terms to alleviate their financial strain.

5. Technology Transfer: Developing nations emphasized the importance of technology transfer to bridge the technological gap between developed and developing countries. They called for the exchange of technology on fair and equitable terms, as well as the establishment of research and development centers in developing countries.

Impact and Challenges:
- The NIEO brought attention to the issues faced by developing countries and sparked a global debate on economic justice and equality.
- However, the NIEO faced significant opposition from developed countries, who were reluctant to make substantial changes to the existing economic order.
- The failure to implement the NIEO in its entirety led to frustration among developing nations and a shift towards other strategies for economic development.
- Some elements of the NIEO, such as debt relief and technology transfer, have since been incorporated into international development agendas.

In conclusion, the NIEO was a significant attempt by developing countries to reshape the global economic system and address the imbalances between developed and developing nations. While it faced challenges and was not fully implemented, it brought attention to the issues faced by developing countries and contributed to the ongoing discussions on economic justice and equality.