How did rulers attempt to control the trade routes during the sixth century BCE?

By offering protection for a price

During the sixth century BCE, the subcontinent witnessed the emergence of a vast network of land and river routes, extending in diverse directions. These routes interconnected through overland paths leading to Central Asia and beyond, as well as maritime paths from ports along the coastline. The maritime routes extended across the Arabian Sea to reach regions like East and North Africa, West Asia, and through the Bay of Bengal to Southeast Asia and China. Rulers of different regions sought to control these crucial trade routes and often offered protection in exchange for a fee.