Besides, instructions for blocking 1,791 Uniform Resource Locators (URLs) including Facebook pages and YouTube videos have been issued by the DoT to ISPs in 2016 and 2017 (till November 30), Telecom Minister Manoj Sinha said in a written reply to Lok Sabha.
"DoT has directed ISPs to block the list of 4,694 URLs of child sexual abuse material as provided by Central Bureau of Investigation," Sinha said.
Also, a total of 2,133 URLs were blocked in order to comply with the directions of various courts in 2016 and 2017 (till November 30), he added.
Sinha said ISPs implement blocking of Internet websites/URLs by using suitable technology.
"However, at present, technically it is not feasible to block specific items or content contained in a particular URL/webpage," he noted.
In response to a separate query, Minister of State for Electronics and IT Alphons Kannanthanam said a total of 587, 964, and 1,329 URLs of social media websites/specific webpages were blocked in 2015, 2016 and 2017 (up to November 30), respectively.
"Further, a total of 632, 100 and 83 URLs of social media websites/web pages were blocked in compliance with the directions of the competent courts of India in 2015, 2016 and 2017 (up to November 30), respectively," Kannanthanam said.
The government does not regulate content appearing on social networking sites, Kannanthanam said adding that law enforcement and security agencies make searches on the Internet on specific case-to-case basis or as appropriate.
"As per the data maintained by National Crime Records Bureau (NCRB), a total of 2,423 persons in 2014, and 3,137 persons in 2015 were arrested under combined sections of 66 and 66A of IT Act," he said.
Kannanthanam said there have been attempts from time to time to penetrate systems/devices of cyber networks operating in government and its personnel. "These attacks have been observed to be originating from the cyberspace of a number of countries including China and Pakistan," he said.
Citing data from Indian Computer Emergency Response Team (CERT-In), the minister said 44,679, 49,455, 50,362, and 40,054 cyber security incidents were observed during 2014, 2015, 2016 and 2017 (till November), respectively.
The types of cyber-security incidents include phishing, scanning/probing, website intrusions and defacements, virus/malicious code, ransomware, denial of service attack etc, Kannanthanam added.
CERT-In issues alerts and advisories regarding latest cyber threats/vulnerabilities and countermeasures to protect computers on regular basis.
Kannanthanam said 15 drills have so far been conducted by CERT-In to assess cyber-security preparedness of organisations. About 148 organisations from different states and sectors such as finance, defence, power, telecom, transport, energy, space, IT/ITeS etc participated in these drills.
A 24/7 security monitoring centre including NIC-CERT is also in place at NIC (National Informatics Centre) for detecting and responding to security incidents, he said.