How “economic concentration’’ in the hands of a few, harmful to the Overall business development in an economy?

The extent to which a market is taken up by producers within a given industry.

It is a function of the number of firms and their respective shares of the total production (alternatively, total capacity or total reserves) in a market.

As an economic tool it is useful because it reflects the degree of competition in the market.

There are game theoretic models of market interaction (e.g. among oligopolists) that predict that an increase in  concentration will result in higher prices and lower consumer welfare even when collusion in the sense of cartelization (i.e. explicit collusion) is absent. Examples are Cournot oligopoly, and Bertrand oligopoly for differentiated products.

Agreed to Mr. VJ