Washington, March 1: Reliance Industries chairman Mukesh Ambani again topped 84 Indian billionaires in Forbes 2016 list of the world's richest people once again headed by Bill Gates with a net worth of $75 billion. Mukesh Ambani with a net worth of $19.3 billion was ranked 36th among world's 1,810 billionaires with an aggregate net worth of $6.48 trillion, down from $7.05 trillion last year. Technology guru Gates, who has topped the list for 17 of the last 22 years was followed by Spanish clothing retailer Amancio Ortega, best known for the Zara fashion chain, with Warren Buffett remaining in the third spot. The US led with the greatest number of billionaires, with 540, followed by China with 251, Germany with 120, India with 84 and Russia with 77. China had the most of 198 newcomer billionaires, adding 70 to the list. Thirty-three newcomers were from the US, 8 from India and 28 from Germany. Notable newcomers included Flipkart cofounders Sachin Bansal and Binny Bansal (No. 1476) of India. India's top ten: 1 (world ranking 36) Mukesh Ambani $19.3 bn; 2 (44) Dilip Shanghvi $16.7 bn; 3 (55) Azim Premji $15 bn; 4 (88) Shiv Nadar $11.1 bn; 5 (133) Cyrus Poonawalla $8.5 bn; 6 (135) Lakshmi Mittal $8.4 bn; 7 (184) Uday Kotak $6.3 bn; 8 (196) Kumar Birla $6.1 bn; 9 (219) Sunil Mittal $5.7 bn; 10 (233)Desh Bandhu Gupta $5.5 bn. Telecom mogul Carlos Slim Helu (No. 4) dropped two spots, and his net worth decreased to $50 billion from $77.1 billion last year. Amazon's Jeff Bezos (No. 5) moved up to the fifth from the fifteenth spot last year; his net worth increased to $45.2 billion. Facebook's Mark Zuckerberg (No. 6) moved into the top 10 for the first time. He was the biggest gainer with his fortune going up by $11.2 billion for a total net worth of $44.6 billion. He is the sixth richest in the world. The biggest loser was Helu.