First underground drainage system was introduced by which civilization:

🧠 Explanation:

The Indus Valley Civilization introduced the first underground drainage system. For history students, this highlights ancient history, making it a key topic for studying archaeology, South Asian history, and engineering. Drainage advanced cities. Understanding this clarifies urban planning. It’s essential for analyzing history, archaeology, and South Asian studies. Studying the drainage system offers insights into how civilizations built cities, crucial for history, archaeology, and engineering.