My question is regarding najasat from disbelievers. We work in the workplace with them and it’s hard sometime to cope up. Example during a rainy day when one of them got into the car wet and sat on the seat making it najis. Recently it was raining and I got into the car on the same seat. That seat would make my clothes najis and unable to pray.
What should be done?

You can refer in this issue to Sheikh Nassir Makarim Sheerazi, who says that all human being are pure, as it is a precautionary issue according to S. Sistani