350 DC is the District of Columbia chapter of the far-left radical environmentalist group, 350.org. The chapter, like its parent organization, is opposed to the extraction and use of conventional energy.
The organization supported the Shut Down DC environmentalist protest on September 23, 2019, that blocked and slowed down traffic in Washington, D.C., in order to force action on climate change. It is a part of All Out D.C., a radical-left activist group that formed after the election and inauguration of Donald Trump as President. 
The goals of 350 DC and the rest of the Shut Down DC participants are the end of all fossil fuel extraction and legislation recognizing the “rights of nature” which would end the harvesting of natural resources. 
The organization’s independent online presence is a Facebook page that has around 2,500 followers  and a Twitter account.