While enumerating main characteristics of CFC-11, explain the current issues and controversies around it.

CFC-11 is known as trichlorofluoromethane and is one of the many chloroflurocarbon chemicals that were developed as refrigerants.
Characteristics of CFC 11: When CFCs break down in the atmosphere, they release chlorine atoms that are able to rapidly destroy the ozone layer which protects us from ultraviolet light. They are also potent greenhouse gases that contribute to atmospheric warming.
Current issued regarding CFC-11

• China has been illegally emitting�CFC-11which was banned.
• CFC-11 was the second most abundant CFCs and was initially seen to be declining as expected. However in 2018 a team of researchers found�that the rate of decline had slowed by about 50% after 2012.
• CFC-11 was phased out under the 1987�Montreal Protocol. Despite being the signatory to the Montreal Protocol, China continued to emit the polluting gas.
• Emissions of CFC-11 were on the rise since 2013. In fact, the emissions increased by 25 per cent since 2012.

China has the world�s largest polyurethane foam market. Chinese foam manufacturers have been using CFC-11 illegally to save on the higher cost of alternatives, such as hydrochloro-fluorocarbons like HCFC-141b. But this gas still contributes one-quarter of all chlorine reaching the stratosphere, and a timely recovery of the ozone layer depends on a decline in CFC-11 concentrations.