The Indianapolis Motor Speedway drew in 135,000 racing fans Sunday for the 2021 Indianapolis 500, in what may be the most-attended sports event in the United States since the pandemic started. While that number is just 40 percent of the track’s unofficial capacity, pictures posted to social media show packed stands and relatively few masks in some sections, while other sections are more spaced out. In a report in The Indianapolis Star last week, racetrack officials conceded that adherence to mask-wearing rules has been relatively low. While the CDC has said vaccinated people can go maskless outdoors and indoors, sports venues like the IMS are still allowed to impose their own stricter regulations. Indiana is lagging somewhat behind the national average in terms of vaccinations, having reached 42.35 percent of its total population vaccinated with at least one dose.