Explanation:

• The defining event of Ashoka’s rule was his campaign against Kalinga (present-day Odisha) in the eighth year of his reign.
• This is the only recorded military expedition of the Mauryas. The number of those killed in battle, those who died subsequently, and those deported ran into tens of thousands.The campaign had probably been more ferocious and brutal than usual because this was a punitive war against Kalinga, which had broken away from the Magadha Empire (the Hathigumpha inscription speaks of Kalinga as a part of the Nanda Empire).
• Hathigumpha inscription at Udayagiri caves is the main source of information about Kalinga ruler Kharavela. This inscription, consisting of seventeen lines has been incised in deep cut Brahmi script.

Source: Tamil Nadu state board