Article 3 defines the scope of income considered to be realised within Qatar. This includes gross income from local activities, contracts executed wholly or partly in the state, and income from real estate located in Qatar, including capital gains. It also encompasses income from shares in resident companies, service fees paid to associated entities, interest on local loans, and income from the exploitation of natural resources. This article establishes the 'source' principle, ensuring that all economic activity tied to the territory of Qatar is subject to the national income tax regime.