There have been many incidences where the Google Adsense Account Activation request of many publishers were rejected by Google. And as Google does not state the Exact reason why the Request wasn’t approved, it keeps the publisher wondering what he did wrong. It must be noted that Google is getting very strict these days regarding the Adsense Account approval as people are trying to Fool the Advertisers and Make easy money.
People from the Asian Sub-Continent have been increasingly caught in Adsense Fraud Activities so the rules are stricter for them. Let us consider a few reasons why adsense account request of Publishers is not being approved.
1. Not hosted on a Domain name i.e. Hosted on some free Sub-domain.
2. Domain Name not even least 6 months old.
3. Website not getting enough traffic [at least a 100 visitors per day]
4. Website does not have unique content [Content is Copied from Wikipedia or from other websites indexed by Google]
5. Content is only about latest events [Like Latest Technology News and nothing else]
6. Website does not satisfy Google Adsense policies [read the Adsense policies in detail, you may find a reason there]
7. You are filing the application with a directory under the Domain name [like domain.com/xyz]
8. You are not having enough content on your website. [minimum 30 pages]
9. You are using Black Hat tricks for SEO.
Bonus tip: Use Original Information and a Google Account [Gmail Email Address] to apply for Adsense Account. And verify your site ownership in Google Webmaster Tools.