(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 that:

1. (1) the city or town has adopted and approved a smart growth zoning district;
2. (2) the certification has not been revoked by the department;
3. (3) the district is being developed in a manner that reasonably complies with the applicable minimum requirements set forth in section 6 for housing density and affordability;
4. (4) the plan approval 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 and this chapter.