Which event brought about a profound change in Ashoka's administrative policy?

The Kalinga War (ended c. 262 BCE) was fought in what is now India between the Maurya Empire under Ashoka and the state of Kalinga, an independent feudal kingdom located on the east coast, in the present-day state of Odisha and north of Andhra Pradesh . The Kalinga War included one of the largest and bloodiest battles in Indian history. Despite an unexpectedly fierce resistance from the Kalingans, the Maurya Empire claimed victory and annexed the state of Kalinga. Kalinga did not have a king as it was culturally run without any. This is the only major war Ashoka fought after his accession to the throne. The bloodshed of this war is said to have prompted Ashoka to adopt Buddhism.