Which historical region hosted a saiga population that has shown no field records since the 1970s, indicating local extinction?

Answer

China (Junggar basin and Beita Mountains)

A distinct saiga population existed in the Junggar basin and Beita Mountains area of China, but there have been no field records from this location since the 1970s.

Which historical region hosted a saiga population that has shown no field records since the 1970s, indicating local extinction?
subspeciessaiga