The Google-owned service bans all conspiracy theory videos falsely linking coronavirus symptoms to 5G networks
YouTube tightened its policies after a live-streamed interview with conspiracy theorist David Icke, in which he had linked the technology with the coronavirus pandemic, broke the internet earlier this week.
According to theBBC, Icke falsely claimed "a link between 5G and the prevalent health crisis".
And when asked for his reaction to reports of 5G masts being set on fire in England and Northern Ireland, he responded: "If 5G continues and reaches where they want to take it, human life as we know it is over... so people have to make a decision."
Several users subsequently called for further attacks on 5G towers in the comments that appeared alongside the feed.
In addition to his above claims, the theorist professed that a coronavirus vaccine, when one is developed, would include "nanotechnology microchips" that would allow humans to be controlled.
He added that Bill Gates - who is helping fund COVID-19 vaccine research - should be jailed. His views went unchallenged for much of the two-and-a-half-hour show.
The controversial interview was watched by about 65,000 people as it was streamed, some of whom clicked an on-screen button to trigger payments to make their live chat reactions stand out.
However, YouTube only deleted the content after the session had ended, despite being aware of the broadcast while it was ongoing.
It changed its rules after the BBC questioned why the video was permitted. "We have clear policies that prohibit videos promoting medically unsubstantiated methods to prevent the coronavirus in place of seeking medical treatment, and we quickly remove videos violating these policies when flagged to us," a YouTube spokesperson told the BBC.
"Now any content that disputes the existence or transmission of COVID-19, as described by the WHO [World Health Organisation] and local health authorities is in violation of YouTube policies.
"This includes conspiracy theories which claim that the symptoms are caused by 5G.
"For borderline content that could misinform users in harmful ways, we reduce recommendations. We'll continue to evaluate the impact of these videos on communities around the world."
As repercussions, YouTube notified that users who repeatedly break the rules will now not be able to use YouTube's Live tool.
The firm may also prevent repeat offenders from earning money, and said it would terminate channels as a last resort.