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," he said. "My father has never in 88 years told me that he loved me. We don't do that."

Kissing scenes were banned by Indian film censors until the 1990s. But 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. 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.

"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 whom 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.

Even so, Aseem Chhabra, a columnist for The Mumbai Mirror, an English daily featuring local news, said public displays of affection are still a rare sight. "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.

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.

The New York Times