The concept of Gandhian trusteeship is an important idea that can help to promote human dignity and social justice. It challenges the existing economic system that is based on greed and exploitation and offers a more ethical and sustainable alternative. Elaborate in 400 words.

Write it in the format of intro, body, and conclusion. 

In body part cover the following sections: 

1.concept of trustee with real life examples, 

2. it's need and benefits, 

3. challenges of this model, 

4.what should be done to overcome these challanges. 

Write the content of respective sections in bullet points.