Yes, Flikr has blocked Indian IPs for default safe search.

If your Yahoo! ID is based in Singapore, Hong Kong, India or Korea you will only be able to view safe content based on your local Terms of Service (this means you won’t be able to turn SafeSearch off). – Flickr help 

I am a user of Flickr and I really don;t understand this, I have never came across any such photo that can be called Porn.