A full 12,564 sites have been banned in the country, according to TorrentFreak. The move is an attempt to stop people distributing leaks of 2.0, a brand new Indian film.
The movie is the most expensive ever to be made in the country, and has just been released amid a flurry of publicity.
But studios fear that people will distribute it online, leaking it and getting it for free rather than paying in cinemas.
Even despite the wide-ranging block, the film is thought to be circulating online and is easily available through torrenting sites.
Some 37 internet companies will now have to ban all of their users from accessing those sites, to keep the film protected.
It comes as India cracks down on internet sites that citizens can access generally. The country has been launching intense crackdowns on pornographic and adult websites, to broad criticism.
The pre-emptive order – which was given before the film was actually released, let alone made available online – is thought to be one of the most wide-ranging ever to be granted.