Your CSV is malformed. If you are going to have a comma within a field that field needs to be enclosed in quotes.
Header1,header2
Abc,"xyz,pqr"
Ab,"pd,ss"
If you want that to be an array that will be loaded by powershell later and used as an array then you probably want to export the object as XML rather than a CSV since that supports nested arrays.
If this is a CSV that is generated by some other application that you are trying to load into PowerShell then you will need to parse the file yourself and probably won't be able to use Import-CSV. Something like:
$Imported = Get-Content $file | Select -Skip 1 | ForEach {[PSCustomObject][Ordered]@{'Header1'=$_.Split(",")[0];'Header2'=$_.Split(",")[1..2]}}
Alternatively you can store the CSV with a different delimiter so maybe it would look more like (semicolon delimited):
Header1;Header2
Abc;xyz,pqr
Ab;pd,ss