section_path: Geography/Environment
section_name: Environment
paragraph_text: Environment
  
  Environmental issues in New York City are affected by the city's size, density, abundant public transportation infrastructure, and its location at the mouth of the Hudson River. For example, it is one of the country's biggest sources of pollution and has the lowest per-capita greenhouse gas emissions rate and electricity usage. Governors Island is planned to host a US$1 billion research and education center to make New York City the global leader in addressing the climate crisis.
  
  As an oceanic port city, New York City is vulnerable to long-term manifestations of global warming like sea level rise exacerbated by land subsidence. Climate change has spawned the development of a significant climate resiliency and environmental sustainability economy in the city. New York City has focused on reducing its environmental impact and carbon footprint. Mass transit use is the highest in the country.
  
  New York's high rate of public transit use, more than 610,000 daily cycling trips as of 2022, and many pedestrian commuters make it the most energy-efficient major city in the United States. Walk and bicycle modes of travel account for 21% of all modes for trips in the city; nationally, the rate for metro regions is about 8%. In both 2011 and 2015, Walk Score named New York City the most walkable large city in the United States, and in 2018, Stacker ranked New York the most walkable American city. Citibank sponsored public bicycles for the city's bike-share project, which became known as Citi Bike, in 2013. New York City's numerical "in-season cycling indicator" of bicycling in the city had hit an all-time high of 437 when measured in 2014.
  
  The New York City drinking water supply is extracted from the protected Catskill Mountains watershed. As a result of the watershed's integrity and undisturbed natural water filtration system, New York is one of only four major cities in the United States the majority of whose drinking water is pure enough not to require water treatment. The city's municipal water system is the nation's largest, moving more than 1 billion U.S. gallons (3.8 billion liters) of water daily from a watershed covering 1,900 square miles (4,900 km 2)
  
  According to the 2016 World Health Organization Global Urban Ambient Air Pollution Database, the annual average concentration in New York City's air of particulate matter measuring 2.5 micrometers or less (PM) was 7.0 micrograms per cubic meter, or 3.0 micrograms within the recommended limit of the WHO Air Quality Guidelines for the annual mean PM. The New York City Department of Health and Mental Hygiene, in partnership with Queens College, conducts the New York Community Air Survey to measure pollutants at about 150 locations.