Can I be eligible to take my SAT Subject Test if my passport is under?
Technically, no. The testing centre is not supposed to allow you to take the examination if your passport is expired. I'm assuming the country you live in requires you to present a passport as a form of identification at the SAT. (India does) However, some centres may be more lenient about this. Take any other identification you may have (government ID, Aadhar), and hope for the best. I also suggest you ask around and find out if any centres in your area are especially lax about such security measures, and if possible, test there.