Currently i am in USA since last 1 year and I have iphone 13 with primary sim (eSIM) as my USA number and Secondary as my India number (physical sim). The secondary line (India number) says SOS only in system services. What could be the reason.

It sounds like your iPhone 13 is the USA model with frequencies for the North American networks. This is not a problem while you continue to use it in USA.

With regard to the Indian SIM showing SOS, that indicates that the SIM does not have roaming access for billable calls using the available networks in USA, but it WILL be allowed to make emergency calls. That means you could use it for 911 calls only. There are two possible reasons for this - either (a) your network in India does not have a current roaming agreement with the USA networks, -or- (b) Your account at the India provider and its SIM have been put on stop or the account has been closed. This might happen because (for example) the SIM has not connected to its home network in India for 12 months.

Hi PRC2022, it could be that the Indian sim is not connecting to the USA service towers. which will often happen when having a overseas sim in you’re phone unless you’re Indian service provider let’s you use your SIM card int’l.

Or it could be that the Indian mobile company canceled you’re sim for some reason.