The DGR are rules based on the International Civil Aviation Organization's (ICAO) Technical Instructions. The DGR include the United Nations classification of each article or substance and their acceptability and conditions for air transport. The DGR is not an official regulatory document and the regulations contained within the DGR are not permitted to be less restrictive than the law.
While the ICAO Technical Instructions are updated every two years, the DGR are updated annually. According to IATA, "the need to stay current with the individual country and airline restrictions, which can be more restrictive than ICAO regulations, require more up-to-date information."