(a) Any structure which casts a new shadow upon the aforementioned commons only during the first hour after sunrise or before seven o'clock in the morning, whichever is later, or the last hour before sunset.
(b) Any structure in the city of Boston included in a development plan or a master plan within a planned development area, all as approved on or before May first, nineteen hundred and ninety, by the city of Boston Zoning Commission in accordance with chapter six hundred and sixty-five of the act of nineteen hundred and fifty-six, as such development plan ormaster plan may thereafter be amended; provided, however, that such amendment shall not permit construction of a structure which casts additional new shadow on any area of the Boston Common, subject to the one acre exclusion set forth inthe second sentence of subsection (c); or
(c) Any structure within the Midtown Cultural District established by Article 38 which casts no new shadow for more than two hours from eight o'clock in the morning through two-thirty in the afternoon on any day from March twenty-first to October twenty-first, inclusive, in any calendar year, on any area of the Boston Common. Notwithstanding the foregoing, authorization may be granted by a permit-granting authority for a structure which casts a new shadow on the Boston Common beyond the aforementioned two hour period if the area shaded at the end of such two hour period does not exceed one acre, such area to be calculated as the sum of the areas of new shadow cast at any time beyond the two-hour limit by all structures in the Midtown Cultural District approved by the city of Boston Board of Appeal after March twentieth, nineteen hundred and eighty-nine, whether or not exempt pursuant to subsection (b).
Any structure within the South Station Economic Development Area established by Article 40 east of Atlantic avenue and north of Beach street which casts a new shadow upon the Boston Common only during the first hour after sunrise or before eight o'clock in the morning, whichever is later, or during the last hour before sunset.
