Hong Kong (CNN Business) Google is reportedly planning to get back into China, a lucrative market where it has a long history of tangling with authorities.

China has hundreds of millions of internet users and a thriving online shopping market, making it impossible for US tech companies to ignore. But jumping back into China presents ethical issues for Google ( GOOGL ), which has long advocated a free and open internet.

Andy Tian, a tech executive who formerly led mobile strategy and partnerships for Google in China, said the Chinese tech companies that currently dominate search can't compete with Google's product.

"There's a huge void, Google can fill that void," said Tian, who is now CEO of Asia Innovations.

Asked about The Intercept report, Google said in a statement that "we don't comment on speculation about future plans."

Like many other US internet platforms, Google's most popular products — search, YouTube, Gmail — have been banned in China for years, blacked out by a vast government censorship apparatus known as the Great Firewall.

But that wasn't always the case.

Google China 1.0

Google launched a Chinese language version of its search engine — Google.cn — in 2006. It complied with Beijing's censorship laws.

"While removing search results is inconsistent with Google's mission, providing no information (or a heavily degraded user experience that amounts to no information) is more inconsistent with our mission," Google said at the time.

While the search engine was censored, it also flagged to users when information was removed from results. That gave Chinese internet users an idea of what they were not allowed to see.

"We reminded users in China every single day that they are looking at filtered results," said Tian, who worked at Google when the search engine launched.

Still, critics complained that Google was breaching its own company motto: "Don't Be Evil."

The company's devotion to web freedom, critics charged, was being subverted by a willingness to comply with Chinese censorship in return for access to a huge potential customer base.

Attack and retreat

Google was battling Baidu ( BIDU ) for market share. Three years after launch, Google had wrestled about a third of the search market away from its Chinese rival.

The dynamic changed in January 2010, when Google charged that Chinese hackers had targeted Google and more than 20 other Western companies and compromised the email accounts of Chinese dissidents living abroad.

Beijing denied that it had been involved in the attacks, but the incident sparked a political fight with Washington.

A laptop screen displaying the landing page google.cn, which linked to an uncensored Hong Kong site on July 1, 2010, in Beijing.

About three months later, Google made good on a threat to stop offering search in China.

In March 2010, it announced it had stopped running the censored Google.cn service and began routing its Chinese users to an uncensored version of Google based in Hong Kong.

Academics, university students and other researchers relied heavily on Google's search services to access information not available through Chinese search engines like Baidu.

Businesses that depended on Google applications such as Google Docs and Gmail also suffered.

Google wants back behind the Firewall

Google's parent company Alphabet changed its motto in 2015, replacing "Don't Be Evil" with "Do the Right Thing."

From a business perspective, getting back into China is the right thing for Google. It currently offers just a few services in the country — Google Translate, a file organizing program and a new AI game.

Advertising is Google's main source of revenue, and 1.4 billion potential users are hard to ignore. Facebook ( FB ) which competes with Google for advertising revenue, is also locked out of China.

Shares in Baidu dropped 8% on Wednesday after The Intercept report was published.

Critics and human rights groups are already accusing Google of bending to China's will.

"The reality is that they will be serving the Chinese government," said Lokman Tsui, former head of free expression for Google in Asia.

"The government now tracks people, apps on phones reveal who you are, where you are. They are intrusive," he added. "They collect much more data and Google can be requested to handover these data to the government."