Why government can't block Porn sites?

Indian Government is successful at blocking lot of torrent sites. But, not the sites that are holding Porn content.

If they say that increase in human trafficking and drugs usage are related to the online porn content. 

Why can't they stop it, How difficult is it for them? If offices can block such sites why can't the Government itself can do it?

The answer is simple, on an average apart from Social networking sites most people watch or download Porn online. 

Now people prefer to watch it online rather than sharing it through portable media, for which you need to go to the source to acquire it.

With online watching you have absolute privacy to the type of content you want to watch and a additional bonus is that there are no embarrassing jokes in front of your friends, about the content and the frequency you are watching it.

Because of above stated reasons people prefer to watch it online for which you need to have enough band width. 

Obvious that you don't want a wheel showing that you have to wait for the content to buffer. 

So, you go and buy more bytes from the service provider which in turn generates revenue. 

The Reasons for Not Blocking the Content:

1 Now, as said that the service provider's one of the main source of revenue is Online Porn. 

I think and speculate they are not allowing the Government to block the content. 

2 Government has made a study where not watching Porn leads to more frustration in people leading them to concentrate more on what is happening around

in the country which will have adverse affects on the voting style. 

3 Government is happy to maintain the status-quo until some thing adversly goes wrong as they are getting paid for that.

P.S: All the above stated speculations are speculations and not True. 

As i don't have any proof, i am considered  speculating.