Q:
How is it to do imamat and pray Namaaz in Pants?
A: In the past only British used to wear pants. One who wore pants
used to be considered a British. But now Muslims, Hindus and other nations
wear
pants excessively. Therefore now the pants are not a dress of any particular
nation. If a dress, which is not particular to a nation or used to be
particular to a nation but it's now a common dress will not be called
a specific dress of any nation. Even though that dress was invented by
a nation. Syedna Alahazrat Imam Ahmad Raza Muhaddise Barelvi Aleh Rehmat-o-Riawan
writes in Fatawa-e-Rizvia in Part 9 on page 91 that "Only that resemblance
is prohibited or Makrooh in which a person's intention is to resemble
or that thing is a way of Bud Mazhab or holds some kind of state against
Shariat.
In the absence of these mentioned conditions definitely there is no reason
for prohibition" In the same book it is mentioned under Mawahibe
Ludnyah Hazrat Allama Qastalani Rehamatullah Aleh says about the dress
of Jews,*1. Therefore if the pants are loose enough that it will not be
cumbersome to perform Namaaz, it is allowed to perform Namaaz wearing
them. But they should not be so long that they will cover the bones of
ankles otherwise Namaaz will be Makrooh. If it's because of pride it is
Makrooh-e-Threemi otherwise Makrooh-e-Tanzeehi. Strict Muslims in our
area still dislike wearing pants and consider them improper. Therefore
for such an important post of imamat wearing pants is not proper. Syedna
Alahazrat Imam Ahmad Raza Muhaddise Barelvi Aleh
Rehmat-o-Riawan writes,*2
(Fatawa-e-Rizvia, part 9 page 38) Allah Tala knows the best.
*1 
*2 