New Delhi | The Supreme Court on Tuesday declined to direct the reopening of CBSE's portal for the re-evaluation of class 12 answer sheets for students with complaints with the On-Screen Marking (OSM) system.

CBSE's OSM evaluation system is a digital grading method where teachers assess scanned copies of physical answer sheets on a computer instead of checking physical paper scripts.

A bench comprising Chief Justice of India Surya Kant and Justices Joymalya Bagchi and V Mohana said the portal was opened for all candidates for a specified period and reopening could trigger fresh claims.

"Why should we direct them to open this window again for you? If you don't use the bus, you miss the bus. The window was open for everyone for a specified period," the CJI said.

The counsel appearing for the petitioner submitted he was seeking only one week's time.

"The website crashed and many students could not apply for on-screen verification," he said.

Solicitor General Tushar Mehta, appearing for CBSE, told the apex court that 1.68 lakh students successfully applied during the notified window.

The Delhi High Court has already dismissed a similar challenge, he said.

The top court was hearing a plea challenging the manner in which CBSE introduced the OSM system for evaluation of answer sheets.

It alleged that the introduction of digital scanning resulted in several irregularities, including certain pages of answer sheets not being scanned, illegible scans and answers or pages not being evaluated.