This episode contains descriptions of severe injuries.Tough new border policies introduced by the Biden administration have sharply reduced the number of migrants crossing into the United States. But the measures have also created a combustible bottleneck along the southern border. That situation exploded last week when a deadly fire broke out at a detention center in Ciudad Juárez, Mexico.Simon Romero, a national correspondent for The Times, explains how the United States has leaned more heavily on Mexico to help handle its immigration dilemma, bringing cities like Juárez to a breaking point.Guest: Simon Romero, a national correspondent for The New York Times covering the Southwest.Background reading: Mexican officials have announced that they are investigating the fire as a homicide case.There has been a relentless buildup of migrants in Mexico, where shelters are overwhelmed and the authorities have a checkered record on human rights.For more information on today’s episode, visit nytimes.com/thedaily. Transcripts of each episode will be made available by the next workday.