Question

With minor exception, which of the following have been phased out completely globally?

(a) Carbon dioxide

(b) Carbon monoxide

(c) Chlorofluorocarbons

(d) Nitrogen dioxide

I got this question by my college director while I was bunking the class.

Origin of the question is Kyoto Protocol and Montreal Protocol in chapter Social Issues and the Environment of Energy Management

Answer 1

Right answer is (c) Chlorofluorocarbons

To elaborate: Chlorofluorocarbons (CFCS) is one of the ozone depleting substances. Release of chlorofluorocarbons leads to the damage of the ozone layer. With a very minor exception, CFCs have been phased out globally.