Praise be to Allah.
The Prophet (peace and blessings of Allaah be upon him) wore the thawb (qamees), the rida’ and izaar (upper and lower garment) and sirwaal (pants). With regard to the Pakistani dress (shalwar khameez), it is not narrated – as far as we know – that the Prophet (peace and blessings of Allaah be upon him) wore this type of dress.
Undoubtedly adhering to this Arabic dress comes under the heading of preserving the ummah’s customs and unique characteristics, and protecting it from imitation of others and assimilation. This is undoubtedly better than western dress.
However, clothing is considered to come under the heading of traditions, and each country has its own traditions and customs, and there is nothing wrong with a Muslim following the traditions of the country he lives in with regard to dress, on condition that it does not include anything haraam in the material of which it is made or the way in which it is designed. So it is not permissible to wear silk, or tight clothing, or see-through fabrics that show the ‘awrah, or clothing that belongs uniquely to the kuffaar or that is made of silk.
Neither is it permissible to wear “garments of fame and vanity” – which means things that a person becomes famous for wearing – because the Prophet (peace and blessings of Allaah be upon him) said: “Whoever wears a garment of fame and vanity, Allaah will clothe him in a similar garment on the Day of Resurrection.” A report from Abu ‘Awaanah adds: “Then it will burst into flames.” Narrated by Abu Dawood, 4029; classed as hasan by al-Albaani in Saheeh Abi Dawood, 3399.
It was narrated that Ibn ‘Umar said: “The Messenger of Allaah (peace and blessings of Allaah be upon him) said: ‘Whoever wears a garment of fame and vanity, on the Day of Resurrection Allaah will clothe him in a garment of humiliation.’” Narrated by Ibn Maajah, 3606’ classed as hasan by al-Albaani, 2905.