India's pharmaceutical sector emerged as the one that gave investors the best returns over the past year, according to a survey of the global rich, a ranking of billionaires around the world.

The wealth of billionaires who invested in the Indian pharma increased by an average 25 per cent, according to the Hurun Global Rich List 2014, sponsored by a Chinese luxury property developer.

This might come as a surprise in a year when the Congress-led government, hobbled by a series of scams, has attracted accusations that it has fostered crony capitalism and favoured a few oligarchs while privatising scarce natural resources such as telecom spectrum, coal and gas, allowing the oligarchs to rake in super profits.

Among these oligarchs is Mukesh Ambani, the managing director of Reliance Industries, India's second-largest company by net sales. He continues to be the richest Indian, but the company's share price fell by five per cent, a loss that pulled him 14 positions down in the global list, to 27 from 41.

Reliance Industries stands accused of having received hugely generous terms from the government for supplying gas from fields that it won the rights to explore in 1999, something both the company and the government deny.

London-based Lakshmi N Mittal, the chief executive of Arcelor Mittal, the world's largest steel producer, retained his number two position in India but slipped 13 positions on the global list to 49 after the company's share price dropped 6 per cent. He also figures in the top three of UK's rich list.

Dilip Sanghvi of Sun Pharma ranked third among Indian billionaires, with the company's share price rising by 52 percent.

Also in the top 10 were two billionaires from the information technology sector, Azim Premji, chairman of Wipro, who tied with Sanghvi, and Shiv Nadar, founder and chairman of HCL.

Other pharma billionaires on the long list include Yusuf Hameid of Cipla, Malvinder and Shivinder Singh of Fortis Healthcare, GV Prasad of Reddy's Lab and Murali Divi of Divi's Lab.

Overall, India ranks fifth in the list, accounting for 89 billionaires. Of them, 70 live in the country while the remaining are of Indian origin. Half the Indian billionaires on the list live in Mumbai.

These calculations are based on a snapshot of individuals' wealth on 17 January 2014.