New Delhi, June 3 : The Central government on Thursday announced extension of the validity period of Teachers Eligibility Test (TET) qualifying certificate from seven years to a lifetime with retrospective effect from 2011. Union Education Minister Ramesh Pokhriyal 'Nishank' made the announcement instructing the state as well as Union Territory (UT) governments to revalidate or issue fresh TET certificates to those candidates whose period of seven years has already elapsed. Pokhriyal said this will be a positive step in increasing the employment opportunities for candidates aspiring to make a career in the teaching field. The Teachers Eligibility Test is one of the essential qualifications for a person to be eligible for appointment as a teacher in schools. The guidelines dated February 11, 2011 of the National Council for Teachers Education (NCTE) laid down that TET would be conducted by the state governments and the validity of the TET Certificate would be seven years from the date of passing the TET. /IANS