As India’s economy modernizes, millions of young people are moving into urban gated communities of apartment buildings. But the economic prosperity has also engendered a lifestyle that discourages neighborly ties. (Bloomberg Via Getty Images)

Sumit Jain has fond memories of his childhood in a small town where everybody knew everybody. But as a young man, he moved to a big city for work and began living in an apartment building. Jain said he soon missed feeling connected to a community.

That sense of loss led him to create, a “neighborhood portal” for Indians whose lifestyles have changed with their nation’s economic transformation but who still crave neighborhood life. A sort of hyper-local version of Facebook, Commonfloor creates online communities for the half-million users in 30,000 apartment buildings across 100 cities it has attracted so far.

“Something fundamental is changing among urban Indians today,” said Jain, 27, a software engineer and co-founder of the start-up in the southern city of Bangalore. “We no longer know who our next-door neighbor is, we don’t speak to each other in the elevators, and we cannot knock on the neighbor’s door just to say hello without making them wary.”

As India’s economy modernizes, millions of young people are leaving their parents’ homes to find work, and many of them are moving into apartment complexes in the cities. These fortress-like gated communities — with uniformed security guards and surveillance cameras — are designed to keep strangers out. But neighborly ties are rare as residents adjust to fast-paced lives, long commutes and access to an abundance of technology.

Just a generation ago, Indians took for granted a sense of community that included celebrating festivals with neighbors, attending wedding parties in the neighborhood park and taking homemade treats to the people next door.

Many urban dwellers now mostly keep to themselves and read e-mail alerts to find out what’s going on around them.

“It is a combination of wealth creation and lack of time that has changed people’s socializing patterns in urban India,” said Anshuman Magazine, South Asia chairman of the property consulting firm CBRE, adding that the number of gated apartment complexes has grown by more than 35 percent every year since 2007. “In their free time, people prefer to take their families to the malls, movies and restaurants or go to weekend resorts rather than visit their neighbors.”

Commonfloor seeks to help Indians who do not want to give up their newfound desire for privacy but still secretly yearn for some of the support systems they enjoyed in the past.

The portal not only tells people who their neighbors are, but it also helps them find cooks, maids, plumbers and after-school activity classes for children. It allows people to create subgroups based on shared interests, such as yoga and cricket.

“This e-community does not discourage ‘touch-people’ who like to meet, talk, touch and hug,” Jain said. “But it gives enough privacy to those who only want to meet neighbors electronically.”

By 2030, about 70 percent of the new jobs in India could be created in cities, where more than 600 million people are expected to live, up from 350 million today, according to a report by the global consulting firm McKinsey & Co.

On a recent day, finance professional Gautam Puri reminisced about growing up in the small northern town of Yamunanagar.

“We knew everybody on our street even though we lived in stand-alone homes. We visited the neighbors, asked for help and went for evening walks together,” recalled the 37-year-old, who lives in a New Delhi suburb. “But here I can run into a neighbor from the next apartment five times a day because their door faces mine but still not have a conversation.”

When Subhankar Saha, 38, moved into his lemon-colored home three months ago, he wanted to form a residents’ group on Commonfloor to deal with repairs to the swimming pool, elevators and jacuzzi. But even asking his neighbors for their e-mail addresses has been tricky.

“Their body language sends out a signal that says, ‘Leave me alone,’ ” Saha said.