The Internet Archive provides a hugely useful resource for those who want to see content that's otherwise no longer online, whether that's due to it being taken down or the site that published it going offline. However, for reasons unexplained, the Indian government appears to have blocked access to the two-decade-old service.
As first noted by MediaNama, an Indian tech and telecoms website, people trying to visit the site on Tuesday evening started to find a notice telling them it was blocked, on instruction from the country's Department of Telecommunications.
People have reported the blockage on a wide range of Indian broadband and mobile networks. Typically, when they want to censor a site, governments order internet service providers to block access to its web address. In India, this regularly happens with pornographic websites, sites that promote piracy, and those that are seen as posing a threat to national security.
Get Data Sheet, Fortune’s technology newsletter.
Internet Archive office manager Chris Butler told MediaNama that the government had not notified the U.S.-based outfit before instituting the block, as it had done when it briefly blocked the site a couple years back.
Butler said Internet Archive had no luck trying to get an answer out of the relevant departments as to the reason for the blockade. "Obviously, we are disappointed and concerned by this situation and are very eager to understand why it’s happening and see full access restored to archive.org," he said.
The Internet Archive has around 273 billion web pages and around three million public-domain books, all searchable through its Wayback Machine. It is quite possible that the archive contains material that's otherwise censored in India, though the reason for its blockage will only become clear when the government explicitly states it.