Mukesh Ambani has retained his position as the world's richest Indian for the fifth year in a row, although his networth declined by 1.6 billion to 21 billionUS Dollars but remained well above that of the second-ranked Lakshmi Mittal. He is retaining this position for 5th year ina row. Steel baron Mittal's networth also fell by 3 billion dollars at USD 16 billion, making him the second richest, as per global business magazine Forbes' annual ranking of 100 wealthiest Indians, released today.Mukesh's younger brother Anil Ambani, who heads telecom- to-infrastructure conglomerate Reliance Group, was ranked 11th with a networth of USD 6 billion. Others in top-10 ranking include Adi Godrej at 6th position , followed by Savitri Jindal , Shashi & Ravi Ruia , Hinduja Brothers and Kumar Mangalam Birla.