Hello Engr Salah,
Do you have access to sub-daily satellite rainfall data over Pakistan?
I've been able to use Tropical Rainfall Measuring Mission (TRMM) rainfall estimates to generate IDF curves here in Africa (Nigeria).
TRMM has 3 hourly rainfall estimates, so just do a google search and see if you have such that covers Pakistan, else you will have to look into ways of "downscaling" the 24hr IDF intensity to lower durations using the "simple scaling" method.
Regards
Out of the mire...a spectacle of perfection. #TheLotusConstruct