FATCA stands for the Foreign Account Tax Compliance Act, a U.S. tax initiative that requires all financial Institutes (including Indian Mutual Funds) to report financial transactions of US persons including entities in which U.S. persons hold a substantial ownership, etc. to the relevant tax authorities.
It is introduced by the United States Department of Treasury and the US Internal Revenue Service (IRS), the purpose of FATCA is to encourage better tax compliance by preventing US persons from using financial institutions outside US to avoid US taxation on their income and assets.