Ecologic analysed and compared different sources of data on the production and trade in Ozone Depleting Substances. Reporting data on production, imports and exports of ozone depleting substances (ODS) is one of the most fundamental bases for checking compliance with the Montreal Protocol. There are different sources for generating the necessary data. The European Commission has generally relied on the reporting by producers and importers/exporters as required under Article 17 of Regulation (EC) 3093/94 to generate the needed information. These data have provided the basis for submitting the annual data required under Article 7 of the Montreal Protocol to the Secretariat of the Protocol in Nairobi.