Section 90. Power to prevent or demolish building

If any person without the permission of the Trust erects, adds to or alters any building or wall so as to make the same project beyond the street alignment or building line shown in any plan finally adopted by the Trust, x x x the Trust may, by a written notice- (a) direct that the erection, alteration or addition be stopped, and (b) require such building or wall to be altered or demolished, as it may deem necessary.