Indians are increasingly taking to smartphones and the number of such devices in the country touched 40 million last year with almost half of the users younger than 25, says a survey.

The dramatic growth in the usage of smartphones is driven by a desire among users to stay connected and have instant access to social networking sites, according to the survey by research firm Nielsen.

"Decreasing device and data costs, coupled with a wide range of features that today's smartphones offer, readily encourage consumers to trade in their traditional cell phones for handsets with much more functionality," the survey said.

According to the Indian smartphone user study conducted in September and October 2012 across 46 cities people overwhelmingly prefer mobile devices that operate on the Android operating system.

While Symbian usage is also high in India, Windows, BlackBerry and iOS devices each only have single-digit market shares, said Nielsen Informate Mobile Insights that polled more than 10,000 smartphone owners.

Moreover, tablet ownership among Indians is set to spike as consumer interest in tablets is also on the rise.

While only 3 percent of respondents who participated in the study in the last quarter of 2012 said they owned a tablet, 11 percent said they intended to purchase one.

Voice calls and texting accounted for only 25 percent of smartphone usage multimedia, games, apps and Internet browsing made up the rest.

Among apps, consumers prefer games, particularly with respect to paid apps. Games were the most popular category among paid apps, with nearly three out of five users (58 percent) paying for games.

Other popular paid app categories among smartphone users include chat and instant messaging (53 percent) and streaming music (45 percent).