[Butch Cassidy Slept Here]

Under the US Civil Rights Act of 1964 discrimination, on the basis of religion in the course of boarding public transport, which is operated in interstate or foreign commerce, is prohibited. In addition, if your origin is from the Indian sub-continent you have an additional "protected class," under said Act, of "Asian-Pacific Islander." The mere fact that the act of discrimination took place outside the boundaries of the USA does not, to my understanding, relieve Delta of its obligation of compliance with the Civil Rights Act. Further, the fact that this individual may have been only an employee of a Delta contractor, rather than someone actually on Delta's payroll, also does not relieve Delta of its US Civil Rights obligations. Under US law "the act of the agent (contractor in this case) is the act of the principal (Delta.)"

All that having been said the real problem here is one of proof. Delta can, and probably will, hide behind the US regulations and laws pertaining to air security. Unless you were carrying a hidden recording device and managed to catch this man uttering an anti-Hindu, or anti-Indian, comment its unlikely you'll be able to get any redress. A letter to the Airline Consumer Section of the US Dept. of Transportation, in which you cite your concerns, might some day reign-in the excesses of this not so in the closet redneck assuming similar complaints from others are lodged.

While I'm sure there are many Muslims who have no problems with Hindus, the animosity between the two groups is well known to have existed through most of the 20th century. Accordingly I find it hard to dismiss the possibility that the Delta agent, which you appeared to identify as Muslim, may have had an anti-Hindu bias.