MacOS – PDF Download Only

I am assuming you have permission and are not breaking any laws.

The link you want is

http://krishikosh.egranth.ac.in/bitstream/1/20399/1/24441.pdf 

However, you should not access it if you don't have permission.

The way to locate this is to use a browser with dev tools (most do). In this case, in Chrome press F12

Then in the Elements tab you can locate the link URL by expanding the HTML elements until you find the relevant section.

Update

Another way is to disable the PDF viewer in the browser (this is unlikely to work for the website in your question but may work for other websites). This means that when the PDF is requested, the browser has no tool/method to open the file, and as such will provide it as a download.

The issue may have to do with the way files are served by web servers.

Some servers may include Content-Disposition: attachment header in their response leading to Chrome downloading the file when you click on the download link while others may skip that header in their response, leaving the decision of whether to open or download the file up to Chrome.

More info on this here:
Force to open “Save As…” popup open at text link click for pdf in HTML
Do I need Content-Type: application/octet-stream for file download?

The following solution will download all PDF files including embedded files meant to be viewed within Chrome like the one's here and here. However, it won't work for sites using PDF.js to display embedded PDF files, like this online demo.

Adding or modifying Content-Disposition headers on the fly to Content-Disposition: attachment for MIME type application/pdf should help force Google Chrome to download all PDF files.

You can achieve this with the Modify Content-Type extension.

1. Install the extension and click on the extension icon in the toolbar and select Options
2. Click on Add Rule and add the following rule:

   Name:               Download PDFs
   URL Filter:         .*
   Original Type:      application/pdf
   Replacement Type:   application/pdf
   Disposition:        attachment
   

3. Click Save Rule
4. Refresh the page containing the PDF links so that the extension is loaded for that that page