N.Y.C. Admin. Code § 27-2085

f. Not more than one apartment, as recorded either in the certificate of occupancy or legally existing and recorded in the department prior to nineteen hundred twenty-nine, shall be located in the cellar unless the yard is sixty feet or more in depth. Such dwelling unit shall contain no more than five rooms and a bathroom and shall be occupied either by the janitor or a rent-paying tenant if no member of the family is under the age of sixteen years. No required window in any room of such apartment shall open upon a court less than five feet six inches in width. Every part of such dwelling unit shall be located within twenty-five feet of the inner surface of the front or rear wall of the dwelling or shall have a window opening upon a court not less than twelve feet in width.