How to import the certificate in web browsers

In Mozilla Firefox .cer extension can be used directly. Else use following sequence of links after downloading the certificate.
Go to about:preferences#privacy, then go to "View Certificates" –> Authorities.
then import the CA certificate.

Figure 3.3.1: Importing the certificate in Mozilla Firefox

In Google chrome, use following sequence of links after downloading the certificate.
Seetings --> Show advanced settings... --> Manage certificates... --> Trusted Root Certificate Authorities --> import.

Figure 3.3.2: Importing the certificate in Google Chrome

Import a CA certificate in Centos7.

# cp ROOTCA-iitk.ac.in-cacert.pem /etc/pki/ca-trust/source/anchors/
# update-ca-trust extract