Explanation

In August 1989, 44 countries and EEC ratified the Montreal protocol, which provides a mechanism to review the efficiency of control measures. In a policy statement called Helsinki Declaration, the attending nations agreed to phase out the production and consumption of controlled $CFCs\$as soon as possible but not later than the year 2007. They also agreed to phase out the halons and to control and reduce other Ozone Depleting Substances (ODSs).