If, during the MND process, there is substantial evidence, in light of the whole record, that the project (even with revisions) may have a significant effect on the environment that cannot be mitigated or avoided, the lead agency shall prepare and circulate a draft EIR, and certify a final EIR prior to approving the project.

If new information of substantial importance or substantial changes to a project or its circumstances occur after adoption of a MND, the lead agency shall prepare a subsequent EIR if the change will have a significant effect on the environment or, shall determine whether to prepare a subsequent MND, an addendum, or no further documentation is required.

Reference:

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