NEW DELHI -- India may be the birthplace of the Kama Sutra, the ancient how-to manual on kissing and sex. But for many years, Indian couples did not widely embrace kissing, at least not in public. Now that is changing.
The Mahabharata, an epic poem written 3,000 years ago, is believed to include the first written description of mouth-to-mouth kissing. But anthropological studies done over the past century in India and elsewhere in Asia showed that kissing was far from universal and even seen as improper by many societies, said Elaine Hatfield, a professor of psychology at the University of Hawaii.
Sanjay Srivastava, a professor of sociology at the Institute of Economic Growth at Delhi University, said: "Until recently, kissing was seen as Western and not an Indian thing to do. That has changed."
In India, most marriages are still arranged, and the rate of sex before marriage is low, according to a government survey, so passionate kissing among the unmarried has long been discouraged. Many married couples refrained as well, at least in front of other people. But recent studies, backed by interviews with sociologists and psychiatrists in India, suggest that kissing's popularity has risen considerably.
Chastity is viewed as highly desirable in India, and Indians, as a result, have also tended to view outward expressions of love, be they physical or verbal, with suspicion, said Dr. Roy Abraham Kallivayalil, president of the Indian Psychiatric Society.
"I don't tell my wife that I love her," Dr. Kallivayalil said. "My father has never in 88 years told me that he loved me. We don't do that."
A study led by James Witte, a professor of sociology at George Mason University in Virginia, reported that more than half of a set of volunteer respondents in India said they kissed at least several times a week. He solicited respondents through Internet portals, in English, but cautioned that his sample was not random. He said he reached people who were "well educated, younger and more urban" and who had access to the Internet.
In Professor Witte's study, of the 112 respondents in the kissing module, 24.1 percent said they kissed passionately "many times a day," but when asked about kissing, hugging or caressing in public, 41.1 percent of participants chose "hardly ever or not at all."
A pivotal screen kiss reflected the changing romantic landscape here. Kissing scenes were banned by Indian film censors until the 1990s, and Shah Rukh Khan, a Bollywood heartthrob who is one of the world's biggest movie stars, has been teasing Indian audiences in dozens of films since then by bringing his lips achingly close to those of his beautiful co-stars. But his lips never touched any of theirs until he kissed the Bollywood bombshell Katrina Kaif in "Jab Tak Hai Jaan," which was released in December 2012.
Mr. Khan tried to soften the impact by saying in a published interview that his director made him do it. But the cultural Rubicon had been crossed.
"That kiss was an incredibly important moment," Dr. Srivastava said. "Shah Rukh Khan defines what is mainstream. If he does it, it becomes acceptable."
Kissing's rise here may also reflect the growing power of young women in deciding who to marry, said Debra Lieberman, an assistant professor of evolutionary psychology at the University of Miami. In many cases, "women are now able to select mates without having to negotiate as much with family members," Dr. Lieberman said.
And Dr. Avdesh Sharma, a psychiatrist practicing in New Delhi, said that his younger female patients are far more insistent than their mothers were that their emotional needs be met. That often involves kissing, he said.
"The terms and timing of intimacy used to be initiated and decided entirely by the man," Dr. Sharma said. "That is no longer true."
Indeed, while arranged marriages are still the norm in India, a growing share of young couples say that their views play a role in the process. If a young woman does not like the man her parents have picked, many families now offer her a veto.
Prakash Kothari, the founder of the department of sexual medicine at Seth Gordhandas Sunderdas Medical College in Mumbai, said that his female patients are much more demanding than they once were.
"For years, most Indian men used sex with their partners as a kind of sleeping pill, and few devoted any time to foreplay," Dr. Kothari said. "Now, many women are able to ask for what they want."
Aseem Chhabra, a columnist for The Mumbai Mirror, an English daily featuring local news, said public displays of affection are still a rare sight in India. "It's not like you can walk on the streets of Delhi and Bombay and see people kissing. It's still a big taboo," he said.
"The educated 20-somethings are watching a lot more Hollywood films," he said. "It's not like they are imitating, but they are getting inspired."
Six years ago, Richard Gere caused a national scandal when he kissed the Bollywood actress Shilpa Shetty during an AIDS-awareness event. Mr. Gere quickly fled India, leaving legal complaints and at least one arrest warrant in his wake. Ms. Shetty was criticized for failing to resist him.
A 2006 government-financed survey, the most recent available, found that less than 1 percent of female respondents and 5 percent of male ones said that they had had sex outside of marriage in the previous year. Other studies suggest that premarital sex rates are higher than reported in official surveys, but the numbers are still very low compared with those in the West.
Rajat and Neha, two 22-year-olds in New Delhi's majestic Lodi Gardens, agreed to discuss why they enjoy kissing when their parents had not done so, at least in front of them.
"Love," Rajat said simply as Neha nodded. Their parents' marriages were arranged; they hope to marry for love. They asked that their last names be withheld, however, in part because they are from different castes and fear that her parents would not approve.
Rajat and Neha expect to graduate from college this spring; they say their physical relationship has not gone beyond kissing and cuddling. They met four years ago in a park when he approached and asked if she would be his friend. She agreed but soon suspended the relationship for seven months while she studied for her last set of high school exams.
"It was very hard to spend a day without her," Rajat said. "A single day."
Soon after the exams, she called him. She had memorized his telephone number because she did not want her parents seeing the number in her phone.
"I knew he was waiting for me," Neha said.
They meet regularly in Lodi Gardens, which is far enough from their homes that discovery is unlikely. In contrast to parks in other Indian cities, the police in New Delhi rarely harass young couples in Lodi Gardens. But young men often sit and stare hungrily at kissing couples. On a recent afternoon, kissing couples in Lodi Gardens had the added burden of shooing away a foreign reporter clumsily asking for interviews.
Rajat and Neha say they plan to reveal their love to their parents sometime next year. In the meantime, they kiss -- igniting a bonfire of yearning that fairly leaps off their lips.
"Times have changed," Rajat said. "We are different."
Shreeya Sinha contributed reporting from New York.
This article originally appeared in The New York Times.