Internet service providers in India have installed the most internet filtering systems and blocked the highest number of web pages among 10 countries surveyed in an investigation, The Indian Express reported on Wednesday. The survey was conducted by University of Toronto-based Citizen Lab, along with the Canadian Broadcasting Corporation and The Indian Express.

The investigation covered 10 countries where technologies marketed by Canadian company Netsweeper “appear to be filtering content for national-level internet service providers”, the report said. Netsweeper is a firm which supplies content-filtering solutions to businesses, governments and internet service providers.

As many as 12 internet service providers in India had installed 42 such filtering systems, the report found out. Pakistan was number two with 20 filtering systems. Indian service providers also blocked the highest number of websites – 1,158 out of a total of 2,464 prohibited URLs in the 10 countries.

Pages related to porn and piracy were most frequently blocked, the report said. Other prohibited websites in India included those run by domestic and foreign non-governmental organisations, United Nations organisations, human rights groups, health forums, feminist groups and political activists.

Three Twitter handles Prime Minister Narendra Modi follows – @anilkohli54, @tajinderbagga and @i_panchajanya – were blocked at different times. Some web pages related to ABC News, The Telegraph UK, Al Jazeera, some “related to the Rohingya refugee issue, and the deaths of Muslims in Myanmar remain blocked even in 2018.

Unidentified officials in the Ministry of Electronics and Information Technology told The Indian Express that they had not issued any instructions to block these websites.

The study covered Afghanistan, Bahrain, India, Kuwait, Pakistan, Qatar, Somalia, Sudan, UAE and Yemen.