Demanding that the Central Bureau of Investigation should investigate the matter, thousands of students assembled outside the Staff Selection Commission’s office at CGO Complex in New Delhi.
The agitation that began on Tuesday demanded that the government should take action against the perpetrators responsible for the "paper leak".
The Jawaharlal Nehru University Students Union, the National Students Union of India, and the All India Students Association have also joined the protests on Thursday.
The SSC has organised CGL tier 2 online examinations which were attended by around 1.9 lakh candidates between February 17 and February 22. Students have alleged that the question paper was leaked and found circulating on the social media before the exam was conducted.
Candidates took the examination between February 17-22, but the February 21 test was “delayed”.
"The Commission had conducted Tier-II Examination of CGLE, 2017 from 17.2.2018 to 22.2.2018 across the country. On 21.2.2018, due to incomplete downloading of data on account of some technical reasons, the examination was delayed and candidates faced inconveniences," the SSC said in a statement released on its website on February 24.
Students have alleged “mass cheating” in the examination and said the question paper was leaked.
Earlier on Wednesday, Thousands of students, chanting 'SSC haye haye', gathered outside the SSC office with a copy of the 'leaked' paper.
Issuing a notice, SSC Chairman Ashim Khurana had said that the protests are being "instigated and sponsored by two coaching institutes/ agencies with vested interests."
However, the students alleged that the SSC chairman is not taking the issue seriously.
"SSC conducts online examination for which the answerkey has not been released yet. When the SSC claims the question paper was not leaked, then from where have we got these papers," an aspirant told ABP News showing a copy of a paper.
Karnpal, a farmer's son, said he was his family's only hope and have gone through various struggles to participate in this examination.
"It hurts us when we get to know that those who were preparing for years are not selected and those who bribe officials can easily get through the exams," he said.
Another aspirant said: "I have been preparing for over three years. I am an engineer but now it's getting difficult for me to even get a job of a peon. My family is so frustrated that they asking me to get any job that comes my way."
Students also raised questions on examination policies and transparency of the Staff Selection Commission.
Two candidates who had successfully qualified the CGL exams in 2015 and 2016 said they haven't received joining letters yet.
"I have qualified the exams conducted in 2015 but haven't got the joining letter yet," student, who belong to Farrukhabad, said.
Another student, Ashish Sharma, said: "I was selected as an auditor in the CGDA with the all India rank of 3095. The result was declared on August 5, 2017. It's been seven months, I haven't even received a single letter yet."
Raising his voice in support of the students, Congress chief Rahul Gandhi said their demand for a CBI probe in the matter is just and fair.
"Mr @narendramodi u have mentioned about India’s youths & abt Demographic Dividend in many of ur speeches. Now see what’s happening under ur nose , a big #SSCExamScam !! Who is accountable? It’s just & fair demand 4m aggrieved students to have a CBI probe.@DrJitendraSingh," he wrote on Twitter.
Congress spokesperson Randeep Singh Surjewala said that the “SSC scam” was “another Vyapam”
"SSC Scam is another #Vyapam. Jobs being sold, future of millions of youth jeopardised, unabated protests continue for 3 days in Delhi, yet Modiji & SSC remain mum. If there is nothing wrong, why no CBI probe? Will PM answer? Will media listen?" he tweeted.
Senior lawyer Prashant Bhushan said: "After Vyapam, a major recruitment scam erupts with State Selection Commission recruitments for Centre. #sscscam. These scams which cheat our youth of govt jobs are leading to unprecedented unrest & anger among our youth. But BJP only pushes divisive issues."