Those productive activities that generate goods and services forbidden by law.

This includes: the production of goods and services, whose sale distribution or possesion is forbidden by law and productiive activities which are usually legal but which become illegal when carried out by unauthorised producers (e.g. unlicensed medical practicioners). There may no be clear borderline between the underground economy and illegal production. For example production, which does not comply with certain safety, health or others standards could be defined as illegal. The scope of illegal production in individual countries depends upon the laws in place.