How often do universities undergo NAAC assessment and accreditation?

Universities and other education institutions undergo NAAC assessment and accreditation every five years. The assessment and accreditation process includes a self-study report, along with the visit from the team and evaluation which is based on certain criterias. Once the assessment of NAAC is over, the institutes and universities are then graded from A++, A+ to D, which are valid for a period of 5 years. With the grading system and the following results, the institutions are expected to maintain or further improve in the span of next five years for the re-accredition.