As you have asked about the recruitment of Sub Inspector (SI) in Central Reserve Police Force (CRPF), Delhi, I want to tell you that currently there is no such recruitment going on.
However, you can check its website to know about the updates about the recruitment.
To check it, you can follow steps given below

GO to CRPF website, the page open look like
(Image)




Then scroll down

Then under Recruitment section, click on View All, the page open look like



Here you will find the information about the recruitment of Sub Inspector (SI) when available.
Here I found following;
Instructions/ Guidelines and formats of documents for Medical of CT/GD-2015 New
Online Recruitment Drive to fill up current/backlog vacancies for the post of Head Constable (Ministrial) New