; (B) represents the geographical distribution of targeted populations; and (C) is not exclusive of areas that are integrally related to the composition of the community. (10) Public housing; public housing agency The terms public housing and public housing agency have the meanings given such terms in section 3(b) of the United States Housing Act of 1937 ( 42 U.S.C. 1437a(b) ). (11) Secretary The term Secretary means the Secretary of Housing and Urban Development. (12) Severely distressed housing The term severely distressed housing means a public or assisted housing project (or building in a project) that— (A) (i) has been certified, by an engineer or architect licensed by a State licensing board, as meeting criteria for physical distress that indicate that the project requires major redesign, reconstruction, or redevelopment, or partial or total demolition, to correct serious deficiencies in the original design (including inappropriately high-population density), deferred maintenance, physical deterioration or obsolescence of major systems, and other deficiencies in the physical plant of the project; and (ii) is a significant contributing factor to the physical decline of and disinvestment by public and private entities in the surrounding neighborhood, as documented by evidence of non-physical distress, such as extreme poverty, including census data and past surveys of neighborhood stability conducted by an applicant or co-applicant or their qualified designee; or (B) was a project described in subparagraph (A) that has been legally vacated or demolished, but for which the Secretary has not yet provided replacement housing assistance other than tenant-based assistance. (13) Significant amendment or change The term significant means, with respect to an amendment or change to a transformation plan, that the amendment or change— (A) changes the use of 20 percent or more of the total amount of the grant provided under this title from use for one activity to use for another