Mass. Gen. Laws ch. 90 § 7O
Current with Act changes effective as of September 9, 2024
No person shall remove or render inoperative, except temporarily for maintenance purposes, any device or element of design installed on or in a motor vehicle or motor vehicle engine in compliance with regulations under the National Emission Standards Act (42 USC 1857f-1), unless such device or element is to be replaced by or modified by another device or element, approved by the registrar, the installation of which will result in a reduction of pollutant emission.
Mass. Gen. Laws ch. 90, § 7O