SDS Studio™Definition: ADR is the UNECE agreement on the international carriage of dangerous goods by road, which together with RID, ADN, IMDG and IATA defines SDS section 14.
ADR assigns each dangerous good a UN number, proper shipping name, class, packing group, labels and tunnel code. It is updated every two years (ADR 2025 is current).
Transport classification is separate from CLP classification; a product can be CLP hazardous but not dangerous for transport, or the other way round.
Air transport is legally governed by the ICAO Technical Instructions; the IATA DGR is the airline industry rule built on them, not a UNECE instrument.