350 NYC (sometimes styled 350NYC) is a child organization of 350.org, a left-of-center environmentalist organization that advocates for a complete elimination of the use of fossil fuels. According to 350 NYC’s donations processor, it is a fiscally sponsored project of the California-based left-of-center nonprofit the Social Good Fund. 
In September 2019, 350 NYC helped organize a Global Climate Strike protest in New York City. Individuals left work and school. Thousands of protestors participated in anticipation of the United Nations Climate Summit to show support for left-of-center environmentalist policy. 
350 NYC provides a guide for how activists can pressure the media to portray severe weather events as effects of human-caused climate change. The guide also instructs activists to pressure the media to use specific environmentalist terminology to make this association and to encourage the implementation of environmentalist policy as a solution. 
350 NYC publicly supported New York state’s Climate and Community Protection Act as a step towards implementing the far-left Green New Deal. The act mandates that New York implement mass infrastructure changes to eliminate carbon emissions by 2030. 
350 NYC advocates for total divestment from conventional fuel companies. The group has pushed New York City pension funds to divest $4 billion dollars from energy investments. 350 NYC has also campaigned to demand that banks stop financing fossil fuel companies, and has advocated in support of a New York City ban on conventional refrigerants. 
350NYC was founded in 2011 by environmentalist activist and film producer Lyna Hinkel. She also co-founded and sat as a chair for the Fossil Free NYC Divestment Campaign from 2012 to 2018. 
According to a notation on the page of its donations processor, 350 NYC is a sponsored project of the Social Good Fund. It is not classified as an independent nonprofit organization and accepts donations through the Social Good Fund. The Social Good Fund is a left-of-center nonprofit organization that funds a number of activist organizations.