The crisp lawns, water fountain and new walking path of Lohia Park attract people of all ages. Middle-aged women wearing tracksuit trousers paired with traditional Indian tops walk the trails with strollers in tow. Frisbees and kites fly in the air. And almost every day, couples embrace under a tree or on the grass, oblivious to all around them.

Priyanka Shivharee, 22, and Rohit Chaudhary, 25, are here because the park, in the northern Indian city of Lucknow, is one of the few places where they can get some privacy.

"Actually the park is a silent place," said Chaudhary, who studies at a local engineering college along with his girlfriend of three years. "We can talk to each other and exchange emotions. So peaceful. That's why we come here."

Couples may not always tell their families or friends where they are going, but it is no secret that parks such as Lohia are romantic hideaways. Greater female mobility, more open media that include sexual imagery in movies and advertisements, the decline of arranged marriages and rise in premarital sex all indicate India is becoming more progressive.

But such change has not gone unopposed. The recriminalisation of gay sex in December and the gang-rape of a woman in a village in West Bengal in January to punish her for an illicit relationship were just two of a series of incidents that showed a conservative reaction that some say is hardening.

Some Indians worry that a victory for the rightwing Hindu nationalist Bharatiya Janata party in the general election, a six-week process that started on Monday and will end next month, could signal more conservative trends in India.

Last Valentine's Day, a local petitioner in Lucknow requested the deployment of security personnel in the parks to prevent so-called "obscene activities". Such "moral policing" has caused controversy across much of India. Young people say police will also act on their own initiative.

"It just happens randomly, the police just come and round up the couples there, even if they're just sitting and talking," said Aditi Gupta, 22, who said she and her friends now avoid going to parks and prefer dates in cafes and cinemas.

Lakshmi Chaudhry, a journalist at the Indian website Firstpost who frequently writes on sexuality, said private bedrooms were a luxury for many Indian couples who share crowded homes with extended families.

"One of the great unseen things is that the police pretend this is immoral, these unmarried couples," she said. "But a lot of them are married couples."

Women who go out with boyfriends or even male companions therefore not only challenge ideas of public or private activities, but also views about their own role in society.

"Women in public always have to have a sense of purposefulness," said Sameera Khan, an author and expert on gender in India. "It's when women want to access public space for pleasure, to wander around, sit on a park bench and read, or hang out with a boyfriend, or as we say, to loiter – that is when Indian society is not okay with it."

Historians say the changes in India – in women's rights, access to new forms of communication and urbanisation, among others – resemble those that lay behind huge shifts in sexual behaviour in Europe in the 18th and 19th centuries.

Faramerz Dabhoiwala, a historian at Oxford University and author of The Origins of Sex, said religious liberty was the most important predictor of sexual freedom.

"You can't have moral freedom without religious freedom," said Dabhoiwala. "Any kind of fundamentalism … that presumes that moral values are absolute is incompatible with individual sexual freedom."

Lucknow's couples, at least, were lucky this year: the high court dismissed the Valentine's Day request to deploy security in the parks.

Abishek Prajapati, 21, said he actually preferred spending time with his girlfriend at Lucknow's most famous Shia mourning hall. Couples often sit outside its many windows and then disappear in its maze of passages. "You'll be able to have more intimacy there," he said.