The top US telecoms regulator has unveiled sweeping plans to overturn Obama-era rules designed to protect an open internet.

The Federal Communications Commission (FCC) chairman, Ajit Pai, plans to repeal “net neutrality” regulations that were championed by tech companies and consumer groups. The rules but have been heavily criticized by internet service providers and Pai.

“The FCC will no longer be in the business of micromanaging business models and pre-emptively prohibiting services and applications and products that could be pro-competitive,” Pai told Reuters. He added that the Obama administration had sought to pick winners and losers and exercised “heavy-handed” regulation of the internet.

“We should simply set rules of the road that let companies of all kinds in every sector compete and let consumers decide who wins and loses.”

The move is likely to spark a furious battle before the FCC’s vote on the proposals on 14 December. About 21m comments were submitted to the regulator as it discussed the proposals, and activists have flooded legislators with more than 250,000 calls condemning Pai’s plans. The FCC’s plans will be challenged in court.

Democratic leader Nancy Pelosi called the decision “an all-out assault on the entrepreneurship, innovation and competition at the heart of the internet”.

Quick Guide Net neutrality Show What is net neutrality? Net neutrality is the idea that internet service providers (ISPs) treat everyone’s data equally – whether that’s an email from your mother, a bank transfer or a streamed episode of Stranger Things. It means that ISPs, which control the delivery pipes, don’t get to choose which data is sent more quickly, or which sites get blocked or throttled (for example, slowing the delivery of a TV show because it is streamed by a video company that competes with a subsidiary of the ISP) or who has to pay extra. For this reason, some have described net neutrality as the “first amendment of the internet”. Why is net neutrality under threat? On 14 December 2017, the US Federal Communications Commission (FCC) voted to scrap regulations protecting net neutrality in America. In a 3-2 vote, the commission repealed the rules, which had been introduced by the Obama administration in 2015 to replace the patchwork of authorisations that had previously regulated the internet. In response, a number of states vowed to introduce their own state-wide protections of net neutrality. Who benefits from the FCC ruling? The most obvious beneficiaries are the large ISPs, who frequently have local monopolies and have now been handed the ability to discriminate between their own services and those of competitors, and charge other companies for access or bandwidth. But larger internet companies, such as Google or Facebook, are also likely to benefit from the decision. They stand little risk of being blocked or throttled, given how unpopular such a move would be, and can afford to pay access fees. They would also benefit from the reduced competition from smaller firms and startups, who are at risk of discrimination from ISPs. Are there implications outside of the US? Other nations have their own net neutrality regulations. The EU, for instance, passed a directive in 2016 guarding some key tenets of net neutrality, although allowing some controversial practices, such as "zero-rating" – declaring some sites free for the purposes of data limits. But globally, internet users will experience the indirect effects of the US decision, since its impact on the competitive market within America's borders will ripple around the world. For some, that could even be positive: if new startups can't get traction in the US, they may decide to relocate elsewhere.

Net neutrality is the principle that all traffic on the internet is treated equally. Its supporters argue that equal access to the internet has been essential in creating today’s dynamic online world.

On the chopping block are rules established in 2015 that prevent broadband companies from charging more for internet “fast lanes” for certain content and from blocking or slowing certain content. Critics charge that removing the rules will hand ISPs control of the internet – allowing them to pick winners and losers by slowing some services while giving preferential treatment to those they favor.

Scrapping the current regime will be a major victory for the broadband and cable industry which fought through the courts to stop the net neutrality regulations. They, and Pai, a former Verizon lawyer, have argued the rules are an unnecessary and costly burden on internet providers that hampers investment and innovation.

“The truth of the matter is that we decided to abandon successful policies solely because of hypothetical harms and hysterical prophecies of doom,” Pai said in a speech about the creation of the net neutrality rules earlier this year.

The fight has divided the tech world and comes as cable providers are moving to take control of more and more online content. On Monday the justice department sued to block AT&T’s takeover of Time Warner, which would hand the telecoms company control of CNN, HBO and Warner Brothers among other assets.

The justice department cited comments from AT&T’s own DirecTV satellite business that “vertically integrated programmers” – which own the means of distribution as well as the content – can “much more credibly threaten to withhold programming from rival [distributors]” and can “use such threats to demand higher prices and more favorable terms”.

Amazon, Etsy, Google, Reddit, Wikipedia and other tech companies have all called for the protection of net neutrality, arguing that it essential in creating the level playing field that has allowed so much innovation online.

Free speech groups too are worried about the FCC’s latest moves. Concerned that it could lead to censorship online. A series of protests are planned for 7 December, the week before the FCC vote, at Verizon stores nationwide.

“This is the free speech fight of our generation, and internet users are pissed off and paying attention,” said Evan Greer, campaign director of Fight for the Future, which is organizing the protest.

“Ajit Pai may be owned by Verizon, but he has to answer to Congress, and lawmakers have to answer to us, their constituents. The corrupt bureaucrats trying to kill net neutrality are hoping to avoid public backlash by burying the news over the holiday weekend. We’re taking our protest from the internet to the streets to make sure that doesn’t happen,” she added.