>The American workers say that India’s Tata Consultancy Services illegally discriminated against them based on their race and age, firing them Question to the Americans: if in the US you don't need a reason to fire someone, how can you prove the company was discriminating you when they fired you if they didn't give a reason.
That's not quite what "at will employment" in the US actually means. What it means is that an employer can fire you at any time for any reason that isn't an unlawful reason. It doesn't mean the employer doesn't have to give a reason at all, or that the employer can simply refuse to give a reason if questioned, particularly if there is an allegation that the firing was for an unlawful reason.