This local law amends the administrative code of the city of New York to prohibit the use of fossil fuels in new buildings and in certain major renovations. The legislation aims to reduce greenhouse gas emissions associated with buildings. The prohibition applies to new buildings and major renovations commencing after certain dates, with different effective dates based on the height of the building, specifically January 1, 2024 for buildings under seven stories and July 1, 2027 for buildings of seven stories or more. Exceptions are outlined for specific building types and uses, including hospitals, commercial kitchens, manufacturing facilities, laundromats, and emergency backup power systems. The law grants the Commissioner of Buildings the authority to establish rules for compliance, further defining the implementation and enforcement mechanisms for this transition away from fossil fuel combustion in new construction.