I was trying to update the existing pods with the pod install command, but it takes forever to run.
The verbose mode shows it was stuck at the following
Updated answer for 2019 - the cocoa pods team moved to using their own CDN which solves this issue, which was due to GitHub rate limiting, as described here: https://blog.cocoapods.org/CocoaPods-1.7.2/
TL;DR
You need to change the source line in your Podfile to this:
source 'https://cdn.cocoapods.org/'