Mark Zuckerberg didn't see this coming.
When Facebook's co-founder proposed bringing free web services to India, his stated aim was to help connect millions of impoverished people to unlimited opportunity.
Instead, critics have accused him of making a poorly disguised land grab in India's burgeoning Internet sector.
The growing backlash could threaten the very premise of Internet.org, his ambitious, two-year-old effort to connect the planet.
Indian authorities are circumspect because the Facebook initiative provides access to only a limited set of websites – undermining the equal access precepts of net neutrality.
The telecommunications regulator is calling for initial comments by today on whether wireless carriers can charge differently for data usage across websites, applications and platforms.
Losing this fight could imperil Facebook's Free Basics, which allows customers to access the social network and select services such as Messenger and Microsoft's Bing without a data plan.
"The India fight is helping shape debates elsewhere," said Pranesh Prakash, policy director at the Centre for Internet and Society, a Bangalore-based not-for-profit advocacy group.
"Activists in other countries such as Brazil, Venezuela and Colombia are watching this debate and will seize the momentum created in India."
Zuckerberg's argument for free web access is based in part on Deloitte research showing that for every 10 people who are connected to the web, one is lifted out of poverty and one job is created.
Facebook argues that by giving people free access to a small slice of the internet, they will quickly see the value in paying for the whole thing.
Zuckerberg has said his biggest challenge in connecting people to the web isn't access to mobile networks, but a social hurdle: he needs to prove to people who have never been online that the internet is useful.
"Who could possibly be against this?" Zuckerberg wrote in an impassioned op-ed in the Times of India this week.
"Surprisingly, over the last year there's been a big debate about this in India."
Zuckerberg's plea underscores what's at stake. Facebook already attracts 1.55 billion people monthly, or about half of the internet-connected global population.
To keep growing, the world's largest social network needs to get more people online. Hence the billions of dollars Facebook is spending on projects to deliver the web to under-served areas via drones, satellites and lasers.
And Internet.org, which now spans 37 nations.
India, as the world's second most populous nation, is arguably the most important piece of Zuckerberg's Free Basics strategy.
But the opposition is fierce. Critics note that the Facebook service doesn't offer web favourites such as Google search.
Facebook has said it would be open to adding more features from competitors, but critics are skeptical of giving the social-networking giant such influence on the internet.
Critics also say that by offering a limited swath of the internet at comparatively slow speeds, the company is creating a poor-man's or diluted version of the web.
That could stifle innovation by disadvantaging Indian start-ups building rival apps, or allow Facebook and its telecommunications carrier partners to act as internet gatekeepers.
One97 Communications, a mobile payment start-up backed by Alibaba Group, is one of several Indian tech companies that have come out against Facebook's plans.
"We are totally against telcos preferring one developer over another," One97 founder Vijay Shekhar Sharma said in a phone interview.
"We are asking for access neutrality. We are hoping that all start-ups will be treated equally."
Facebook is now scrambling to drum up support.
It's started a "Save Free Basics In India" campaign, asking Indian users to support "digital equality" by filling out a form that shoots an e-mail to regulators. That also has the effect of sending notifications to user's friends unless they opt out.
Facebook has also taken out full-page advertisements, including one featuring a smiling Indian farmer and his family who the ads say used new techniques to double his crop yield.
With Siddharth Philip, Adi Narayan and Sarah Frier