There are PDF files which are very long and most of the pages don't provide any essential information. So I want to keep only those pages which are relevant and want to get rid of unnecessary material. I have found threads which provide information on how to edit an epub file but not pdf.
Most of you might feel that solution of this question is same as for "Merge PDF File". They are different in following aspects:
Merging and deletion are different and here I am asking for deletion not merging. If someone likes to give same solution then their answers are duplicate not my question.
The answers given for merging of PDF files doesn't provide solution how to add pages at specific location in a PDF file.
It also doesn't specify how to remove just few pages from a single PDF. Solutions given to "MERGE PDF FILES" just implies how to merge two PDF files using range specification method , in order to omit particular pages.