Q: do mac have viruses?

That is a scam. There is nothing to clean out.

See these user tips for more advice:

Phony "tech support" / "ransomware" popups and web pages

Viruses, Trojans, Malware - and other aspects of Internet Security

Just in case you want a second opinion that is a scam.

Allan Eckert wrote:

 

Just in case you want a second opinion that is a scam.

KeyurIndia wrote:

 

I have come across a problem with browser i am using google crome and it is saying your computer is infected with viruses, but i knew that mac don't have viruses.

kindly suggest me how to clean it.

I have just upgraded with EL Capitan

As others have said, it's a scam.  Stay away from the kinds of sites where scams like that reside.  Install an ad blocker extension (I had Adblock recommended to me, and so far it's worked out marvelously), and in Safari Preferences --> Security, make sure "Block pop-up windows" is checked.