In the aftermath of last year's Indian elections, Devu Chodankar, a 31-year-old shipbuilder in Goa, took to Facebook to vent about Prime Minister Narendra Modi's win.

In one post, Chodankar warned that "If Modi is elected as PM this election, Christians will lose their identity in South Goa. Mark these words." In another: "There is imminent threat of Holocaust as it happened in Gujarat through the garb of cunning government policies of Parrikar." He was referring to Modi's role as Chief Minister of Gujurat, a post he held at a time when communal riots led to the killings of hundreds of Muslims.

A supporter of the prime minister saw the Facebook update and reported it to local police. Chodankar was arrested. "The complaint is against Devu for making inflammatory statements and trying to create communal disharmony," the informer said.

Chodankar is far from the only such case. More than a dozen people were reportedly arrested and questioned for online posts criticizing Prime Minister-elect Modi. In recent years, there has been a rash of arrests based on the hurt feelings of politicians — including a university professor who criticized a political leader, a teenager arrested earlier this month over a Facebook post, and a cartoonist whose work satirized the government. Reports of these arrests contributed to the independent group Freedom House giving India's Internet a rating of only "partly free" in 2014.

But a ruling from India's Supreme Court offers hope. Last week, the Court invalidated Section 66A, a 2009 amendment to India's Information Technology Act. The amendment declared "grossly offensive or menacing character" commentary on social media a crime. But last week, in a wide-ranging 200-page opinion that cited, among others, American Supreme Court Justice Oliver Wendell Homes, the Court ruled Section 66A unconstitutional.

"Section 66A is cast so widely that virtually any opinion on any subject would be covered by it," wrote Judge Rohinton Fali Nariman. Calling the wording in the section "open-ended, undefined and vague," the court also struck down Section 118D of the Kerala Police Act, a similar piece of legislation that would give law enforcement the ability to arrest individuals who caused "annoyance" to others.

For free speech activists, or anyone who has ever left an injudicious or upsetting comment on social media, the end of Section 66A and Section 118D represents a necessary victory years in the making.

It was a 24-year-old law student, Shreya Singhal, who filed the public interest litigation that led to the decision. Hailing from a family of lawyers, including a mother in the Supreme Court, Singhal took up the case after reading report after report of unfair arrests. Bothered by the injustice — "If they got arrested, I or my friends could be arrested in the future too" — she discussed the cases and the broader question of free speech in India with her mother, who encouraged her daughter to file the case.

She was 21 when she first brought the litigation. In comments to Live Mint, she noted that if a citizen of India "says something in a newspaper or on TV, that's fine, but if you say it on Facebook, you get arrested … I think there are so many people in India who are tech-savvy and very vocal about their views." And last week, the court ruled in her favor — and turned the soon-to-be lawyer into a hero in the fight for free speech in India. (The irony? The 20-something social media hero has zero presence on Twitter and only a limited presence on Facebook.)

Why does this lone case matter? Because the sheer size of India's Internet population makes it a critical bellwether for Internet freedom. And that number will only go up. Only 20 percent of the Indian population, or around 243 million people, have internet access, but that has increased at a staggering rate from 2 percent (or 21 million people) just 10 years ago.

That means hundreds of millions of people are poised to experience for the first time what so many of us take for granted each day. The Internet they join will leave a deep impression on their values and habits — especially in regards to freedom of expression. Which is why Shreya Singhal's moment of anger and frustration could have a positive, decades-long impact on how a sizable chunk of humanity communicates on the Internet.