If the curbs on the websites, enforced by ISPs at the behest of the government and certain courts, are not lifted, there will be more attacks on government sites, the group warned.
The Indian arm of Anonymous coordinates with its followers in mainly through its Posterous blog at http://opindia.posterous.com/ and its Twitter account @opindia_revenge.
The group has been a vocal critic of a recent clampdown on websites such as Pastebin, Vimeo and DailyMotion, by ISPs such as Airtel and Reliance.
India has 100 million Internet users, less than a tenth of the country's population of 1.2 billion, but still the third largest user base behind China and the United States.
Image: A member of a hacking group stands between the placards as she participates in a protest against Indian government enacted laws that gives it power to censor different aspects of Internet usage, in Bangalore, India, Saturday, June 9, 2012.