Section 213. Lighting and ventilation of rooms

1. No tenement, its lot or
  any room, public hall or stairs therein shall be so altered as  to  have
  its  light  or  ventilation  diminished  in  any way not approved by the
  department.
    2. In every tenement erected after  April  twelfth,  nineteen  hundred
  one,  every  stair  hall,  public  hall and living room and at least one
  water-closet compartment or bathroom containing a water-closet  in  each
  apartment, shall have at least one window opening directly upon a street
  or  upon  a  lawful yard or court existing on April eighteenth, nineteen
  hundred twenty-nine. Such window shall be  so  located  as  to  properly
  light  all  portions of such hall, room or compartment. Every part of an
  apartment of three rooms or less in such  a  tenement  shall  be  within
  eighteen feet of a street or yard or have a window opening upon a lawful
  inner  or  outer  court  existing  on April eighteenth, nineteen hundred
  twenty-nine. When a room in a tenement opens upon an inner  court  on  a
  lot  line  and less than ten feet wide from the lot line to the opposite
  wall of the dwelling, such room shall be provided  with  a  sash  window
  communicating with another room in the same apartment. Such window shall
  contain  at least ten square feet of glazed surface and be made so as to
  open readily.
    3. No room in any  old-law  tenement  shall  be  occupied  for  living
  purposes  unless  it  meets  the  conditions  in  one  of  the following
  paragraphs:
    a. Such room has a window opening directly upon a street,  or  upon  a
  yard  at  least  four  feet  in depth, or above the roof of an adjoining
  building, or upon a court or shaft at least twenty square feet  in  area
  open to the sky.
    b.  Such room is located on the top story and is adequately lighted by
  a ventilating skylight opening directly to the outer air.
    c. Such room has a sash window opening directly  into  an  immediately
  adjoining room in the same apartment which latter room opens directly on
  a  street  or yard at least four feet in depth. Such window shall have a
  vertically sliding pulley-hung sash not less than  three  feet  by  five
  feet,  except  that  when it is impossible to construct a window of such
  size, the department may permit such window to be narrower. Both  halves
  of  the  sash  shall  be  made so as to open readily, and the lower half
  shall be glazed with translucent glass, or with obscure  wire  glass  if
  the department shall so require. So far as possible such window shall be
  in  line  with windows in outer rooms opening on a street or yard, so as
  to afford a maximum of light and ventilation.
    d. Such room has an alcove opening, of no less dimension than required
  for such a sash window, to such an adjoining room, in  addition  to  the
  usual door openings.
    4.  In  every  existing  tenement  the  department, in addition to the
  requirements of subdivision four of section eighty, may, as often as  it
  deems  necessary, require the walls and ceilings of every room that does
  not open directly on a street to  be  kalsomined  or  painted  white  to
  improve the lighting of such room.
    5.  Notwithstanding  anything in this section to the contrary, no room
  in any old-law  tenement  in  an  apartment  which  is  vacant  on  June
  thirtieth, nineteen hundred sixty, or thereafter becomes vacant, and, on
  and  after  June  thirtieth,  nineteen  hundred  seventy  no room in any
  old-law tenement shall be used for  living  purposes  unless  such  room
  shall have a window opening directly upon the street, or upon a yard not
  less than four feet deep, or above the roof of an adjoining building, or
  upon  a court or shaft of not less than twenty square feet in area, open
  to the sky without roof or skylight, unless such room is located on  the

  top floor and is adequately lighted and ventilated by a skylight opening
  directly to the outer air.
    An  alcove  shall  be  deemed  to comply with the requirements of this
  subdivision if (1) it opens directly into an immediately adjoining  room
  in  the  same apartment, and (2) such adjoining room opens directly on a
  street or yard, and (3) a single unbroken open space occupies  at  least
  sixty  per  centum  of the area of the vertical plane between the alcove
  and such adjoining room. The required open space between any such alcove
  and an adjoining room through which it receives  light  and  ventilation
  shall  not  be  obstructed  by  any  curtain, portiere, fixed or movable
  partition or other contrivance or device.