I had the following code in my .htaccess file to enable Gzip compression:

<ifModule mod_gzip.c>
mod_gzip_on Yes
mod_gzip_dechunk Yes
mod_gzip_item_include file .(html?|txt|css|js|php|pl)$
mod_gzip_item_include handler ^cgi-script$
mod_gzip_item_include mime ^text/.*
mod_gzip_item_include mime ^application/x-javascript.*
mod_gzip_item_exclude mime ^image/.*
mod_gzip_item_exclude rspheader ^Content-Encoding:.*gzip.*

# compress text, html, javascript, css, xml:
AddOutputFilterByType DEFLATE text/plain
AddOutputFilterByType DEFLATE text/html
AddOutputFilterByType DEFLATE text/xml
AddOutputFilterByType DEFLATE text/css
AddOutputFilterByType DEFLATE application/xml
AddOutputFilterByType DEFLATE application/xhtml+xml
AddOutputFilterByType DEFLATE application/rss+xml
AddOutputFilterByType DEFLATE application/javascript
AddOutputFilterByType DEFLATE application/x-javascript

# Or, compress certain file types by extension:
<files *.html>
SetOutputFilter DEFLATE

Now if I want to remove the gzip compression, how can I do so?

I tried deleting the file (didn't work) or entering ONLY the following in the .htaccess file (but still didnt work):

SetOutputFilter DEFLATE
SetEnvIfNoCase Request_URI \.odp$ no-gzip dont-vary

It looks like you might have copied a tutorial somewhere that included 3 different ways of enabling gzip. I'd be surprised if that worked.

Deleting the .htaccess file would certainly disable gzip. If that caused a problem, then just delete all of the code you posted here.

Generally, it's a good idea to enable gzip to speed up your site for users, but it can sometimes cause performance problems if the server is busy.