Section 7. (a) On or before October 1 of each year after the year of approval of a district by the department, the department shall send a smart growth zoning district certificate of compliance to each city or town with an approved district. In order to receive such a certificate, the city or town shall verify within the time specified by the department:
1. that the city or town has adopted an approved a smart growth zoning district;
2. that the certification has not been revoked by the department;
3. that the district is being developed in a manner that reasonably complies with the minimum requirements set forth in section 6 for housing density and affordability;
4. that the approving authority has not unreasonably denied plans for projects, or has only denied plans for projects in a manner consistent with its smart growth zoning district ordinance or by-law, the city or town's comprehensive housing plan and this chapter.
(b) If the department is unable to certify compliance, the department shall hold a public hearing subject to chapter 30A. If the department concludes that the city or town is in material noncompliance with the requirements set forth in this section, the department may revoke certification. A revocation of certification shall be recorded with the registry of deeds or land court registry district for the county or district within which the city or town is located, indexed in the grantor index under the name of the city or town. Any revocation of certification or other sanctions imposed by the department shall not affect the validity of the smart growth zoning ordinance or by-law, or the application of such ordinance or by-law to land, development or proposed development within the smart growth zoning district.