AMSTERDAM—With shops boarded up and riot police out in force, it was relatively calm in Dutch cities on Tuesday night after three days of violence during which nearly 500 people were detained. In several cities, including the capital Amsterdam, some businesses closed early and emergency ordinances were in place to give law enforcement greater powers to respond to the rioting, which was prompted by a nighttime curfew to curb the spread of the coronavirus. On Tuesday when the 9 p.m. curfew went into effect, rowdy crowds of youths gathered in Amsterdam and Hilversum, but were broken up without incident. In Rotterdam, 17 people were detained for violating social distancing regulations. That was in stark contrast to Monday night, when rioting rocked cities across the country and more than 180 people were arrested for burning vehicles, stone throwing, and widespread looting. “This was truly a different picture to yesterday,” National Police …