Is it permissible for him to lead

Q: Is Salah (Prayer) considered invalid if performed while wearing pants or shorts without a shirt. In other words, what is the ruling on offering Salah wearing pants only? It is worth mentioning that in our country, Algeria, almost everyone performs Salah wearing pants without tops except for a small number of people. Some people judge this Salah as invalid or at least doubtful. I ask your Eminence to give us your Fatwa in this regard, and as a seeker of knowledge, I appreciate your detailed answer. I ask Allah to guide us to useful knowledge, good understanding of religion, fruitful efforts, as well as steadfastness and sincerity. Wassalamu `Alaikum.

(Part No. 6; Page No. 170)  A: It is obligatory for men to cover the parts between the navel and the knees with clothes that do not show the skin underneath or the `Awrah (parts of the body that must be covered in public). So, if a person who performs Salah covers the parts that covering is mandatory with material that is not transparent, his Salah will be valid.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.