I think the argument is the Indus Valley civilization was dependent on international trade with the autocracies further west and collapsed when that network broke down
I don't understand your chronology. The LBAC was c.1200 BCE, while the Harappan collapse was c.1900 BCE IIRC.
I think a local process involving drought is more plausible.
I don't understand your chronology. The LBAC was c.1200 BCE, while the Harappan collapse was c.1900 BCE IIRC.