Judgment of the Court (Second Chamber) of 16 April 2026.#Nitrogénművek Vegyipari Zrt. v Nemzeti Adó- és Vámhivatal Fellebbviteli Igazgatósága.#Reference for a preliminary ruling – Environment – Air pollution – System for greenhouse gas emission allowance trading – Directive 2003/87/EC – Transitional rules for harmonised free allocation – Article 10a – National legislation imposing a tax on carbon dioxide (CO2) emissions on operators receiving a significant quantity of allowances allocated free of charge.#Case C-519/24.