The National Testing Agency has sought to explain how a record 67 candidates this year received full marks in the National Eligibility-cum-Entrance Test for undergraduate medical seats amid allegations of irregularities in the results.

The NTA — the government body that conducts multiple entrance tests for medical and dental colleges — has also sought to explain how two candidates received scores of 718 and 719 out of 720.

However, questions remained even after the NTA’s explanation, given in a two-page statement released on Friday night.

The agency attributed some of the 67 full scores and the scores of 718 and 719 to extra marks awarded by an expert panel in response to complaints from candidates about lost exam time.

It said 44 candidates received full scores on account of compensation for a flawed physics question and 6 others received full scores on account of compensation for time lost. It did not say how the remaining 17 candidates got full marks.

Besides, if full marks were awarded for the flawed question, which carried four marks, the students who scored 720 out of 720 would have obtained full marks for each of the other questions, too. The NTA did not explain how these 44 students had obtained 716 out of the 716 marks carried by these other questions.

Nor did it say how many extra marks were awarded for time lost, or how and why time was lost.

Several candidates who had appeared in this year’s NEET-UG, held on May 5, had questioned how 67 candidates scored 720 out of 720 and two others were awarded 718 and 719. The last two scores are, under the marking rules, considered “impossible” because every question carries four marks, with incorrect answers awarded minus 1.

The testing agency said multiple candidates who had taken the NEET-UG this year had petitioned the high courts of Haryana and Punjab, Delhi, and Chhattisgarh seeking consideration for lost exam time on the day of the test.

The expert panel sought information from exam centre staff, studied CCTV footage and decided to compensate the affected candidates based on their answering efficiency and the amount of time they had lost, the NTA said.

It said the panel compensated 1,563 candidates for the loss of time. Their revised marks ranged from minus 20 to 720.

The NTA said it had received 13,000 challenges from candidates relating to the flawed physics question.

“Never in the history of the NEET have so many candidates scored full marks,” Rishi Raj Sinha, national general secretary of the Federation of the All India Medical Associations, a body representing postgraduate doctors, had earlier said. “The NTA should clarify this and the scores of 718 and 719.”

The concerns, amplified via social media platforms, had prompted the Congress to demand a Supreme Court-monitored probe.