1. In C4-7, C5-2, C5-3, C5-4, C6-1A, C6-4, C6-5, C6-6, C6-7 or M1-6 Districts, the City Planning Commission may permit modification of the height and setback regulations, including tower coverage controls, for developments or enlargements located on a zoning lot having a minimum lot area of 40,000 square feet or occupying an entire block.
   
   In C5-3, C6-6 and C6-7 Districts on such zoning lots, and in C6-4 Districts as set forth in paragraph (e) of this Section, the Commission also may modify yard and court regulations, and regulations governing the minimum required distance between buildings and/or the minimum required distance between legally required windows and walls or lot lines, provided that the Commission finds that such modifications:
   1. provide a better distribution of bulk on the zoning lot;
   2. result in a better relationship of the building to open areas, adjacent streets and surrounding development; and
   3. provide adequate light and air for buildings on the zoning lot and neither impair access to light and air to legally required windows in adjacent buildings nor adversely affect adjacent zoning lots by unduly restricting access to light and air to surrounding streets and properties.
      
      As a condition of this special permit, if any open area extending along a side lot line is provided at any level, such open area shall be at least eight feet in width.
2. In C5-3, C6-6 and C6-7 Districts, the Commission may modify height and setback and yard regulations, including tower coverage controls for developments or enlargements located on a zoning lot having an area less than 40,000 square feet, that occupies an entire block front on a wide street, subject to the following conditions:
   1. where buildings or portions thereof penetrate the established sky exposure plane, the aggregate area occupied by such buildings or portions thereof at such elevation shall not exceed:
      1. 55 percent of the area of such zoning lot; or
      2. an equivalent of 55 percent of the aggregate area of such zoning lot and any adjoining zoning lots with a common lot line for at least 90 feet with negative easements limiting height of existing and future developments on the adjoining zoning lots by recorded deed or other written instruments;
   2. that the development or enlargement includes on-site amenities, such as arcades, through block arcades or covered pedestrian spaces where the size and dimensions of such spaces are substantially greater than the required minimum standards, and includes skylights or other provisions for additional access of direct natural light so as to provide for an increased penetration of light and air therein at the street level of the development or enlargement, or a transit station improvement that results in a direct major connection to a subway station.
   3. In lieu of condition (c)(2), the development or enlargement may provide, in the same or an adjoining block of such development or enlargement, compensatory "off-site public open space." For the purposes of this paragraph, (c)(3), the term "adjoining block" shall mean a block that is contiguous to the block containing the development or enlargement but for its separation by a street or street intersection. The area of such off-site public open space shall be at least 4,000 square feet, or 15 percent of the lot area of a zoning lot containing the development or enlargement, whichever is more, and a width of at least 40 feet at any point.
      
      Such public open areas shall have a southern exposure, and adjoin a public sidewalk and be developed pursuant to the provisions of Section 37-70 (PUBLIC PLAZAS). A plan for the development and maintenance of such off-site public space shall be approved by the Commission. The off-site public area shall be kept open to the general public in accordance with a time schedule specified by the Commission. In no event shall such off-site public open space be eligible for floor area or bonus computation in connection with this or any other development or enlargement.
      
      For such developments or enlargements, the Commission may also modify the applicable regulations of Sections 32-51 (Limitations on Business Entrances, Show Windows or Signs) and 36-683 (Restrictions on location of berths near Residence Districts) where adjoining frontage within a distance of 75 feet on the same side of the street is occupied by a community facility or ground floor commercial use, provided that such modification is part of an overall design for show windows, signage and entrances or off-street loading berths developed in conjunction with a public amenity such as a public plaza, through block arcade or covered pedestrian space, and will not alter the essential character of the immediate neighborhood.
      
      In the case of existing buildings containing residences to remain temporarily on such zoning lot, the provisions of Sections 23-70 (MINIMUM REQUIRED DISTANCE BETWEEN TWO OR MORE BUILDINGS ON A SINGLE ZONING LOT) and 23-80 (COURT REGULATIONS, MINIMUM DISTANCE BETWEEN WINDOWS AND WALLS OR LOT LINES AND OPEN AREA REQUIREMENTS) may be modified provided that each and every one of the following conditions are met:
      1. that such existing buildings with unexpired leasehold interests are located upon such zoning lot;
      2. that the portions of the zoning lot where such existing buildings are located and are to be demolished shall be redeveloped according to the approved site plan;
      3. that no temporary or final certificate of occupancy shall be issued for that portion of floor area in the development or enlargement equal to twice the floor area in the temporary existing buildings until such buildings are vacated, demolished and their sites are redeveloped in accordance with the approved project plan, except that where the Commission shall have determined that the applicant for a special permit has made an offer to purchase the leasehold interests from the lessees at a fair market value of the remainder of the lease term, the Commission may decrease the amount of floor area for which no certificate of occupancy may be issued; and
      4. that the development or enlargement conform with all the applicable laws relating to construction, operation and maintenance.
         
         The owner of the zoning lot shall have prominently displayed thereon a sign stating the date by which the buildings are to be demolished.
   4. As a further condition for the issuance of a permit under this paragraph (c), the owner of the zoning lot upon which developments or enlargements are to take place, must post a bond or other security payable to the City of New York and approved by the Corporation Counsel as to form, sufficient in amount as determined by the Commission to cover the cost of demolishing the existing buildings should the owner fail to so demolish within the prescribed time set forth in the approved project plan, and ensure that all floor area which is to be vacant in the development shall remain unfinished and vacant.
      
      The bonds or other securities shall be payable to the City of New York if any of the above conditions are violated.
      
      ​​​​​​​The Commission must find, with each grant for a special permit under this paragraph, (c), that the development or enlargement:
      1. shall result in improved circulation; and
      2. would eliminate the undesirable pre-emption of ground level space by private buildings or other structures.
         
         In making these findings, the Commission may consider the provision of improved connections to rapid transit facilities, where applicable.
         
         The site plan accompanying each application for a grant of special permit under this paragraph (c), shall include a schedule indicating the timetable of demolition of all existing buildings and the schedule of development or enlargement and other improvements on the zoning lot.

In addition to the conditions in paragraphs (c)(1), (c)(2), (c)(3) and (c)(4) of this Section, the Commission shall find that the modification of height and setback will provide a better distribution of bulk on the zoning lot and will not adversely affect other adjacent zoning lots by unduly restricting access to light and air to surrounding public spaces, streets and properties.

1. Notwithstanding any other provisions of the Zoning Resolution, where a development shares a lot line with a landmark building site for an aggregate distance of at least 90 feet, or contains a historically significant street that has been demapped and an archeologically significant site, both of which have been identified by the Landmarks Preservation Commission, the Commission may permit modification of the height and setback and yard regulations regardless of the lot size, provided that the following findings are made:
   1. there is a harmonious architectural relationship between the landmark and the new structure, and such relationship is approved by the Landmarks Preservation Commission or, in the case of a development which contains a historically significant street that has been demapped and an archeologically significant site, there is a visual recognition of the location of the demapped street and of the archeologically significant site created by a design treatment that has been approved by both the Landmarks Preservation Commission and the City Planning Commission and, if such development is located within 200 feet of a historic district, there is a harmonious relationship between the proposed development and the historic district; and
   2. pedestrian amenities are contained in the new structure including, where appropriate, retail stores and substantial pedestrian space at the principal levels of circulation, such as wider sidewalks, arcades, covered pedestrian space, subsurface concourses and convenient subway connections.
2. The City Planning Commission may also permit modification of all bulk regulations as set forth in paragraph (a) of this Section on zoning lots with a minimum lot area of 30,000 square feet, where such zoning lot is located in a C6-4 District in Manhattan Community District 3, has frontage on a wide street and existed on August 8, 2018.