The first CBSE Class X board examination, part of the two-exam system introduced this year, commenced on Tuesday.

The board has clarified that the first exam is compulsory because a section of students had been requesting to be allowed to skip the first exam and appear directly in the second.

The second CBSE exam, scheduled in May, will allow students to improve their performance in any three subjects out of science, mathematics, social sciences and languages, the board has clarified.

“The CBSE had received requests stating that, because of some reasons, students will not be able to appear in the 1st board examination of Class X, hence the students may be allowed to appear in the second board examination.... It is mandatory for all the students to appear in the first board exam,” the CBSE said in the circular on Saturday.

“If a student has not appeared in three or more subjects in the first examination, then s/he will not be allowed to appear in the second examination,” the board has said.

Such students will be placed in the “Essential Repeat” category and can take the examination only next year in the main examination in the month of February, the board has said.

“It is therefore clarified that because of any reason, if a student is not able to appear in three or more subjects in the main examination, s/he cannot be permitted to appear in the second board examination as per the policy of the Board. Any request received by CBSE on the above-cited subject will not be responded to,” CBSE has said.

The first Class X board exam, the main exam, started on Tuesday and will end on March 10.

Several school principals said that over the past few months, they had been informing parents and students that the first board exam was mandatory.

“We had conducted sessions with the parents and led them through the whole procedure that a student cannot skip the first exam, which is being described as the main examination by the board,” said Satabdi Bhattacharjee, principal, The Newtown School.

What several principals anticipate is that some students might want to improve their scores despite scoring high marks. “There is a category of children who are not satisfied even with a 97 per cent,” said the principal of a coeducational school.

The CBSE Class XII exam and ICSE (Class X), which is conducted by the Council for the Indian School Certificate Examinations, started on Tuesday.

ICSE

Every ICSE question paper had a seal that students had to break open when the writing time for the exam started.

Every question paper had a unique identification number and included a watermark that extends across the pages, a strategy introduced by the CISCE this year to curb paper leaks, principals of schools said.