Verb - Evergreen
(third-person singular simple present evergreens, present participle evergreening, simple past and past participle evergreened)
(patents, pharmaceuticals) To extend the term of a patent beyond the normal legal limit, usually through repeated small modifications.
(banking) To set the repayment rate of a loan at or below the interest rate, so low that the principal will never be repaid.
In context of depopulation, looks like BIO-Warfare through pharmaceuticals or Viruses
Non Standard Source: https://www.yourdictionary.com/evergreen