INDIAN WELLS, Calif. — The BNP Paribas Open in Southern California attracts nearly a half-million fans each year. It is one of the top five events on the international tennis calendar.

So when organizers of the event known as “Indian Wells” decided on Sunday to cancel the two-week tournament that had been scheduled to start Wednesday, a new reality descended across the world of sports and entertainment: Every event in the coming weeks, no matter how big, could be in jeopardy.

“If Indian Wells cancels, that is a real sign we’re in a serious situation,” said Donald Dell, the longtime sports promoter and agent.

Indian Wells joined a growing list of events in sports, entertainment and commerce that have been canceled over fears of coronavirus, which has been blamed for nearly 4,000 deaths worldwide and infected more than 100,000 people since its outbreak in Asia in late December. South by Southwest, the music festival and corporate conference in Austin, Texas; Alpine skiing’s season-ending World Cup races in Italy; and even the TED2020 conference scheduled for Vancouver, British Columbia, in April, all have been canceled in recent days.