Section 15(1)(a) in The Bureau of Energy Efficiency (Terms and Conditions of Service of Employees) Rules, 2017
(a)if he is, in a post equivalent to Group `A' or Group `B' post in the Central Government in a substantive, quasi-permanent or temporary capacity and had entered the service of the Bureau before attaining the age of thirty-five years, after he has attained the age of fifty years; or