**2. History and evolution of chloro flouro carbons (cfc)**

The emergence of chloro flouro carbons which are popularly known as CFC has not happened in a day. Natural refrigerants like water, carbon di oxide were used in


#### **Table 1.**

*History and evolution of chloro flouro carbons.*

refrigeration and air conditioning industry in the past which did not impose any destructive effects to the environment and ozone layer. Later on, chloro flouro carbons were introduced by the company Dupon in the year 1930, as a result of remarkable developments in the refrigeration industry. CFC's were released to the atmosphere carelessly during service and repairing of refrigeration and air conditioning equipment. Then it reaches the topmost layer of the atmosphere and destroys the ozone layer, which leads to many harmful effects to humans, animals and crop cultivation. Below **Table 1** shows the brief history and the evolution of chloro flouro carbons.
