On what basis are the companies segregated into different categories in exchanges?

Also what are the different types of securities that are categorised ?

The Companies are segregated based on what Industry does its revenue gets generated from. For example, AUTO, IT etc. From that, the companies are sub-categorised based on what Sector does its revenue gets generated from. 


Automoble Manufacturing

		<p>Auto Ancillaries,</p>

		<p>Product Developement</p>

		<p>Service Outsourcing</p>