gameranand
Living to Play
For an already created PDF you can't do anything about it. But if you are creating one yourself then reduce the image size and quality and other color effects in the pdf to keep the size at minimum.
gameranand
Living to Play
Well I have no experience about Urdu but it depends on the source also. I mean if you combine the pages from a scanned document and combine them for a single PDF then it will be bigger than normal for sure.
Flash
Lost in speed
PDF is already "Portable Document Format", You can't reduce further.
In your case, it should be because of the font scripts.
From WIKI,
"Two PDF files that look similar on a computer screen may be of very different sizes. For example, a high resolution raster image takes more space than a low resolution one. Typically higher resolution is needed for printing documents than for displaying them on screen. Other things that may increase the size of a file is embedding full fonts, especially for Asiatic scripts, and storing text as graphics."
In your case, it should be because of the font scripts.
From WIKI,
"Two PDF files that look similar on a computer screen may be of very different sizes. For example, a high resolution raster image takes more space than a low resolution one. Typically higher resolution is needed for printing documents than for displaying them on screen. Other things that may increase the size of a file is embedding full fonts, especially for Asiatic scripts, and storing text as graphics."