Is it permissible for an employee whose workplace is over 100 km away to shorten and combine prayers, performing Dhuhr prayer at or outside the workplace and Asr prayer on the way back home?

If the distance from the last houses of one's town of residence to the workplace is considered a distance that permits shortening prayers (qasr), then it is legislated to shorten the prayers. Accordingly, it is sunnah (definition) to shorten the Dhuhr and Asr prayers that a worker performs during work. It is permissible for him, before entering his homeland, to combine Dhuhr with Asr, or Maghrib with Isha, either by combining them early (jam' taqdim) or delaying them (jam' ta'khir).