A violation of religious freedom
At the time, he was notorious for failing to take action to prevent the 2002 riots in Gujarat, which broke out after 59 Hindu pilgrims died in a train fire. In a wave of anger, blame was placed on the Muslim community. The ensuing violence lasted for three days. It has been described as a pogrom: over a thousand Muslims were killed and countless homes and businesses were destroyed.
Modi, as Chief Minister, failed to bring the situation under control. Some suggest that he was even complicit in the violence, and the media described the events as “state terrorism”. Later, Modi never expressed regret for what happened, and the state did not launch any formal investigation.
The US barred him from entering the country on grounds of religious freedom. Officials cited a provision of the Immigration and Nationality Act, that "makes any government official who was responsible for or directly carried out at any time particularly severe violations of religious freedom ineligible for a visa.”