Nilayur Tank is an ancient water conservation measure located in Tamil Nadu. Its origin can be traced back to the Pandyan period. As it is still alive and functional, it is being regarded as an engineering marvel. It has four sluices, one of which bears the name of the Pandyan king, Paraanthaga Veeranarayanan who lived between 860 and 905 AD. He is said to have undertaken significant renovations of the Nilayur Tank. The inscriptions are in Grantha letters. The tank irrigated thousands of acres of farmland in the vicinity which were collectively known as Veeranarayanan Valanaadu, which means the fertile land of Veeranarayanan. The tank is noted for its strategic guidance of the water through underground channels to a stone that splits the stream into 3 smaller streams for release in different directions. Ancient sources like copper plates and inscriptions highlight the importance given by Pandyan kings to water conservation and management – it was considered one of his foremost duties.