Age of Empires II: Definitive Edition (PC) - Achievement - Raging Wildfire

Conquer Delhi at least 5 minutes before the timer expires in the fourth Tamerlane mission "Sultan of Hindustan".

Although timed, this achievement is easy (unless you're really slacking). After winning your initial fight, you can explore the map with your remaining troops, whilst having the longer term goal of boosting your economy and obtaining Trebuchets.
Once you have a decent amount of Trebuchets with a large supporting force, head to Delhi and start aiming for their Castles. Two of them can be destroyed from outside the walls of Delhi, so it's best to do that first and then move in for the remaining two Castles once you've mopped up some of their troops that they try and counter you with.
Unless you take an insanely long time doing this, the achievement is very much obtainable on your first try.