The ancient civilization renowned for its extensive trade networks and use of indigo dye is the Indus Valley civilization, which flourished around 2500 BCE in present-day Pakistan and northwest India. They developed sophisticated urban centers like Harappa and Mohenjo-Daro, known for their advanced drainage systems and standardized weights and measures. Trade was vital for this civilization, linking it to Mesopotamia and other regions. The use of indigo dye, derived from plants, was significant in textile production, evidencing the civilization's advanced knowledge of agriculture and resource utilization.