Mukesh Ambani
Mukesh Ambani (R), chairman of Reliance Industries Ltd, poses with his wife Nita (2nd R), mother Kokilaben (2nd L) and son Akash, before addressing the company's annual shareholders' meeting in Mumbai June 18, 2014.Reuters

Releasing this year's list of top billionaires, Forbes has ranked Indian tycoon Mukesh Ambani as the richest person in India and 39th worldwide.

The 57-year-old Chairman and Managing Director, and the largest shareholder of his $75 billion Reliance Industries accumulated $2.4 billion last year, increasing his networth to $21 billion in 2015. Ambani has maintained his position as the richest Indian for the 8th time in a row. 

Founder and Managing Director of Sun Pharmaceuticals Dilip Shanghvi is the second richest Indian and 44th billionaire in the world, with a networth of $20 billion. 

The third position has been maintained by chairman of Wipro Azim Premji, whose networth is $19.1 billion. Globally, he is the 48th richest person. 

Microsoft co-founder Bill Gates continues to the richest person in the world, with a networth of $79.2 billion in 2015, up from $76 billion last year.This is the 16th time he has been ranked as the world's richest person in the last 21 years, said Forbes.

The other top 10 Indian billionaires include founder and chairman of HCL Group Shiv Nadar, ranked 4th (66th globally) with a networth of $14.8 billion.

The fifth richest Indian is 64-year-old Chairman and CEO of world's largest steel-making company ArcelorMittal, Lakshmi Mittal, with a networth of $13.5 billion. Worldwide, he is ranked as 82nd richest person.

Chairman of Aditya Birla Group, Kumar Mangalam Birla is the sixth richest Indian, with a networth of $9 billion.

Executive Vice Chairman and Managing Director of Kotak Mahindra Bank, Uday Kotak (networth $7.2 billion) is the seventh richest Indian.

Chairman and founder of Adani Group Gautam Adani, Chairman and Group CEO of Bharti Enterprises Sunil Mittal and Chairman of Poonawalla Group Cyrus Poonawalla are the other richest Indians, each with a networth of $6.6 billion.