As the Indian tectonic plate crashed into Eurasia 8 million years ago, it did more than build mountains; it altered global weather. New analysis by researchers at the Birbal Sahni Institute of Palaeosciences, Panjab University, and Jamia Millia Islamia of Miocene-era sediment from the Himalayas shows that this uplift, combined with a drop in global temperatures, weakened the monsoon.