N.Y.C. Admin. Code § 27-2057: § 27-2057 Lighting and ventilation in multiple dwellings; general requirements.

a. No multiple dwelling shall be so altered as to diminish the light and ventilation of any room in any way not approved by the department.

b. Every required window shall be so located as to light properly all portions of the room.

c. Any obstruction of required light and ventilation shall be unlawful.