Rishi - I have slightly modified your post for reasons above.
There could be several reasons why your CPC may be down:
1. You could be running multiple websites and one of them may have been smart-priced.
2. It may be a holiday or a weekend.
3. You are operating in a niche for which the prices may have come down for everyone (like a blog on woolen clothes will have low CPC rates in summer)
4. You have blocked lot of sites in your AdSense dashboard and that may include some high-paying advertisers as well.
Personally, I don't block sites because Google is pretty good at taking care of MFA sites in Adwords now.