Which major political and economic development occurred around 600-500 BCE in the Ganga Valley?

Urbanization in the Ganga valley

Urbanization in the Ganga valley occurred around 600-500 BCE.

Invasion of Alexander of Macedon took place in 4th century BCE.
Accession of Chandragupta Maurya took place in 4th century BCE.
Rise of the Chalukyas in Karnataka happened frpm from 543 to 757 ce and again from about 975 to about 1189.