Introduction:
The Panchayat Raj system is a decentralized form of governance in India that aims to provide self-governance at the grassroots level. It consists of three tiers - Gram Panchayat, Panchayat Samiti, and Zilla Parishad. Each tier has its own set of responsibilities and functions. In this context, the question asks at which level the Panchayat Samiti operates within the Panchayat Raj structure.

Panchayat Raj Structure:
The Panchayat Raj structure consists of the following tiers:

1. Gram Panchayat: It is the basic unit of the Panchayat Raj system and operates at the village level. It is responsible for local self-governance and provides essential services and facilities to the village community.

2. Panchayat Samiti: Panchayat Samiti, also known as Block Panchayat or Mandal Panchayat, operates at the block level. It is an intermediate level of the Panchayat Raj system between the Gram Panchayat and the Zilla Parishad. It consists of elected representatives from various Gram Panchayats within the block.

3. Zilla Parishad: Zilla Parishad is the highest level of the Panchayat Raj system and operates at the district level. It consists of elected representatives from the Panchayat Samitis and is responsible for overall development and administration of the district.

Explanation:
Based on the Panchayat Raj structure explained above, it is clear that the Panchayat Samiti operates at the block level. It acts as a link between the Gram Panchayats and the Zilla Parishad, coordinating the development activities at the block level.

The functions of a Panchayat Samiti include:

1. Planning and implementation of development programs and schemes at the block level.
2. Monitoring the functioning of Gram Panchayats and providing them with necessary support and guidance.
3. Allocating funds to Gram Panchayats for various development activities.
4. Coordination between different departments and agencies for effective implementation of programs.
5. Conducting meetings and discussions with stakeholders to address local issues and concerns.
6. Providing administrative support to Gram Panchayats in terms of personnel, finance, and infrastructure.

Conclusion:
In conclusion, a Panchayat Samiti operates at the block level within the Panchayat Raj structure. It plays a crucial role in coordinating and implementing development activities at the block level and acts as a link between the Gram Panchayats and the Zilla Parishad.