India is set to overtake the US as the second-largest market for smartphones in the world by 2016, according to market research firm eMarketer.

"India will exceed 200 million smartphone users, topping the US as the world's second largest smartphone market by 2016," eMarketer said in a report.

India's growth as one of the biggest markets for smartphones is primarily due to the increasing sale of affordable handsets in the country.

While China will remain the biggest market with 624.7m smartphones in 2016, India will have 204.1m, followed by the US at 198.5m, Russia at 65.1m and Japan at 61.2m.

By the end of 2014, China will top 500m smartphone users for the first time.

Across the globe, there will be more than 2bn smartphones in use by 2016, primarily due to the increasing penetration of affordable handsets in emerging markets.

More than a quarter of the global population will use smartphones in 2015 for the first time and over one-third of consumers worldwide will do so by 2018, according to eMarketer.

"Inexpensive smartphones are opening new opportunities for marketing and commerce in emerging markets where many consumers previously had no access to the Internet," eMarketer added.

By 2017, the US will surpass 200m smartphone users, representing about 65% of the country's total population.

Following are the top 25 countries worldwide ranked by smartphone users in 2014, according to eMarketer estimates.

Top 25 countries worldwide ranked by smartphone users in 2014