Judgment of the Court (Eighth Chamber) of 21 January 2021.#Instituto Nacional de la Seguridad Social (INSS) v BT.#Request for a preliminary ruling from the Tribunal Superior de Justicia de Cataluña.#Reference for a preliminary ruling – Social policy – Equal treatment for men and women in matters of social security – Directive 79/7/EEC – Article 4(1) – Voluntary early retirement – Early retirement pension – Eligibility – Requirement for the pension amount to be received to be at least as much as the legal minimum amount – Proportion of workers of each sex excluded from the benefit of early retirement – Justification of a potential particular disadvantage to female workers – Social policy objectives of the Member State concerned.#Case C-843/19.