Hindi becomes the first Indic language supported by Google Adsense program for monetize website content written in Hindi language. It will be a happy news for publishers who owns websites in Hindi. Google Adsense added this new feature to its custom channel of ad unit. When you create a new Adsense custom channel, select site language "Hindi" to support this feature.
Set Adsense Monetization for Hindi Content
If your pages are in Hindi, create new Adsense unit with custom channel to be set to language Hindi. See the image below how to select Hindi language for custom Adsense channel.
As per Adsense report, my 72% earnings come from Hindi speakers in India who resides mainly in UP, MP, Delhi, Chattisgarh, Haryana, Rajasthan, Himachal Pradesh, Bihar, and Jharkhand. It sounds good for Hindi content eyeing over 50 crores peoples who speaks it across the globe.
See Indian states of my Adsense impressions:

What happens website content in other than Hindi?
Websites with other Indian languages use Adsense for their monetization. Though Google allows to display ads in such cases, CPC and earnings will be very low compared to approved languages. Sooner, we expect all other major Indian languages would also facilitate Adsense monetization privilege so that a majority of website owners can earn a good revenue having higher CPC.

Following are the languages Google currently supports for its Adsense monitize program: Arabic, Bulgarian, Chinese (simplified), Chinese (traditional), Croatian, Czech, Danish, Dutch, English, Estonian, Finnish, French, German, Greek, Hebrew, Hindi, Hungarian, Indonesian, Italian, Japanese, Korean, Latvian, Lithuanian, Malay, Norwegian, Polish, Portuguese, Romanian, Russian, Serbian, Slovak, Slovenian, Spanish, Swedish, Thai, Turkish, Ukrainian and Vietnamese.
Note: Google Adsense is unique advertising program that enables on-line publishers make money just displaying Google's advertisements in their web pages. More...