Proceedings of National Academy of Sciences to submit paper

Why did the Harappan civilisation, which flourished for hundreds of years and once extended across a vast area from northwestern India and across Pakistan, suddenly go into a terminal decline some 4,000 years ago and wither away? Like their script that has remained indecipherable, the question what caused a sophisticated urban culture, capable of great feats of town planning and which had established a trading network that extended across the Middle East, to suddenly collapse is one that has aroused much scholarly debate and writing.