Answer: here are some reasons but they add to one thing ykwim
So Ashoka wanted to capture it and lead his huge army to Kalinga in 262 BC.
Ashoka attacked Kalinga in order to further expand the Mauryan empire. Kalinga also had valuable ports which served as a gateway to trade with the far east. Above all, his grandfather Chandragupta Maurya had tried and failed to conquer Kalinga years before, so Ashoka wanted to succeed where his grandfather had failed.
Step-by-step explanation: