SECTION 1. Section 17 of chapter 40A of the General Laws, as appearing in the 2020 Official Edition, is hereby amended by inserting after the second paragraph the following paragraph:-

Other than an applicant challenging conditions imposed on a permit, a party appealing the grant of zoning relief or denial of zoning enforcement has the burden of establishing that they are aggrieved by the decision appealed. Parties in interest as defined in section eleven shall not be aggrieved solely by virtue of their status as abutters or abutters to abutters within three hundred feet. Any appeal of a grant of zoning relief or denial of zoning enforcement by a person other than an applicant challenging conditions imposed on a permit shall be dismissed unless within sixty days following the filing of appeal pursuant to this section the plaintiff files an affidavit setting forth with particularity the specific harm to the plaintiff's property interest alleged as a result of the decision appealed from and identifying persons with knowledge of said harm and documents that support the allegations made in the complaint or described in the affidavit. In the event that a plaintiff identifies harm from traffic, drainage or other impacts of a technical nature, the filing referenced in the preceding sentence must include the affidavit of an expert qualified by training, certification and education to testify as to impact of the alleged harm on the plaintiff's property interest.