Section 90 also generally restates the discretionary power of the agency contained in the 1992 Act to review a licence where there is a proposal for a substantial change to the emissions; where the condition of the environment or environmental medium in the area of the activity has substantially changed; or where new evidence has come to light or a new standard is prescribed in relation to the emission or its effects on the environment. While the EPA may well, at times, carry out reviews on foot of the circumstances listed in section 99E(5), paragraph (c), at other times, it may not.