I know the main catalyst for his conquests to the west we're due to his anger towards the Khwarazmian Shah and to the east due to his feud against China. But why did he send his generals so far west into Europe when looking at a map of their expanding empire, southern India looked like a much more logical target?
I wrote about this briefly a few years ago: https://www.reddit.com/r/AskHistorians/comments/4msb68/when_steppe_nomads_like_the_mongols_and_turks/d3zveqv/
The article that I reference there is very good on the topic. TL;DR, there were several Mongol incursions into northern India, but the climate of India and the necessity of prolonged sieges of fortified Indian cities was not conducive to the grazing requirements of the Mongolian all-cavalry armies. The also were probably outmatched by Indian soldiers in terms of equipment and training.